Extensible absorbent articles

ABSTRACT

The present invention relates to absorbent articles such as sanitary napkins worn by women. More particularly, the present invention relates to absorbent articles, such as thin sanitary napkins, that are extensible, especially in the longitudinal direction.

This is a continuation of application Ser. No. 08/469,054, filed on Jun.6, 1995, which is a division of application Ser. No. 08/315,315, filedon Sep. 29, 1994 abandoned, which was a continuation of application Ser.No. 07/915,284 filed on Jul. 23, 1992 abandoned, which was acontinuation-in-part of the following U.S. patent applications Ser. No.07/539,779 filed Sep. 12, 1990 (abandoned, and now pending as Ser. No.08/401,665 filed Mar. 9, 1995); Ser. No. 07/605,583 filed Oct. 29, 1990,U.S. Pat. No. 5,324,278; Ser. No. 07/630,451 filed Dec. 19, 1990; Ser.Nos. 07/637,090 and 07/637,571 filed Jan. 3, 1991 (U.S. Pat. Nos.5,304,161 and 5,300,054, respectively); Ser. Nos. 07/769,891 and07/769,607 filed Oct. 1, 1991 (U.S. Pat. Nos. 5,389,094 and 5,354,400,respectively); Ser. Nos. 07/734,392, 07/734,404, and 07/734,405 filedJul. 23, 1991 (U.S. Pat. Nos. 5,281,208, 5,356,405, and 5,334,176,respectively); Ser. No. 07/794,745 filed Nov. 19, 1991 abandoned; Ser.No. 07/810,774 filed Dec. 17, 1991 abandoned; Ser. No. 07/823,797 filedJan. 22, 1992 abandoned; Ser. No. 07/827,555 filed Jan. 28, 1992abandoned; Ser. No. 07/832,246 filed Feb. 7, 1992, U.S. Pat. No.5,344,416; Ser. No. 07/874,872 filed Apr. 28, 1992 abandoned; Ser. No.07/882,738 filed May 14, 1992 abandoned; and, Ser. No. 07/892,398 filedMay 28, 1992 abandoned.

FIELD OF THE INVENTION

The present invention relates to absorbent articles such as sanitarynapkins, panty liners, and incontinent pads. More particularly, thepresent invention relates to sanitary napkins that are extensible or,more preferably stretchable, especially in the longitudinal direction.

BACKGROUND OF THE INVENTION

Absorbent articles such as sanitary napkins, pantiliners, andincontinent pads are designed to absorb and retain liquid and otherdischarges from the human body and to prevent body and clothing soiling.Sanitary napkins are a type of absorbent article worn by women that isnormally positioned between the wearer's legs, adjacent to the perinealarea of the body.

Typically, most of the disposable absorbent articles of the typesmentioned above are made of materials that will not stretch. That is,the materials (and the article itself) will not stretch under the forcesthat the absorbent article is normally subjected to when worn.

The inability of the absorbent articles to stretch causes such articlesto have a number of serious drawbacks. One of the most serious is thatthey are not as comfortable for the wearer as they could be. The wearershould ideally be able to notice a difference between an absorbentarticle that stretches to conform to the wearer's body and with thewearer's movements and an absorbent article that fails to stretch.Conventional sanitary napkins will also fail to move with the wearer'sundergarments, causing the sanitary napkins to shift. Providing thesanitary napkin with stretch properties will permit the napkin to betterconform to the wearer's undergarment and stay in place.

Several patent publications disclose absorbent articles having variouscomponents that are capable of stretching. Such efforts are described inU.S. Pat. No. 2,701,567 issued to Smith, U.S. Pat. No. 3,570,493 issuedto Olsson, U.S. Pat. No. 3,653,382 issued to Easley, et al., U.S. Pat.No. 3,717,150, issued to Schwartz, U.S. Pat. No. 4,013,816 issued toSabee, et al., U.S. Pat. No. 4,041,949 issued to Kozak, U.S. Pat. No.4,166,464 issued to Korpman, U.S. Pat. No. 4,533,357 issued to Hall,U.S. Pat. No. 4,573,991 issued to Pieniak, et al., U.S. Pat. No.4,578,070 issued to Holtman, U.S. Pat. No. 4,596,570 issued to Jackson,et al., U.S. Pat. No. 4,655,760 issued to Morman, et al. U.S. Pat. No.4,731,066 issued to Korpman, U.S. Pat. No. 4,847,134 issued toFahrenkrug, et al., U.S. Pat. No. 4,891,258 issued to Fahrenkrug, etal., U.S. Pat. No. 4,965,122 issued to Morman, U.S. Pat. No. 4,992,324issued to Dube, U.S. Pat. No. 5,011,480 issued to Gossens, et al., andEuropean Patent Application 0 450 541 A2 published in the name ofMorris, et al.

The publications listed above may disclose providing absorbent articleswith one or more stretchable components. The present invention, however,is directed to absorbent articles, such as sanitary napkins, that in anumber of embodiments are comprised entirely of components capable ofstretching to accommodate the movements of the wearer and the wearer'sundergarments. The present application also is directed to a vast numberof embodiments for utilizing stretch properties to improve the fit ofthe absorbent article.

It is an object of this invention to provide an absorbent article,particularly a relatively thin absorbent article, such as a sanitarynapkin, that is capable of extending, or more preferably, stretching.

It is a particular object of this invention to provide such an absorbentarticle that is capable of extending (and preferably stretching) in thelongitudinal direction when the article is worn for improved comfort andfit.

These and other objects of the present invention will be more readilyapparent when considered in reference to the following description andwhen taken in conjunction with the accompanying drawings.

SUMMARY OF THE INVENTION

The present invention provides an absorbent article, such as a sanitarynapkin. The sanitary napkin of the present invention is capable ofextending.

The sanitary napkin, however, may be extensible in length (i.e., in thelongitudinal direction) and/or width (i.e., in the transversedirection), and/or in other directions. The sanitary napkin ispreferably also elastically extensible.

The sanitary napkin of the present invention, in one embodimentcomprises an extensible liquid pervious topsheet, an extensible liquidimpervious backsheet, and an extensible absorbent core. The absorbentcore is positioned between the topsheet and the backsheet. The topsheetand backsheet are joined together around the periphery of the sanitarynapkin. The sanitary napkin also comprises a fastener for attaching thesanitary napkin to the crotch region of the wearer's panties. Thefastener is capable of permitting at least portions of the sanitarynapkin to extend in the longitudinal direction.

A number of different types of structures suitable for the abovecomponents of the sanitary napkin are disclosed. A number of alternativeembodiments for the overall structure of the sanitary napkin are alsodisclosed.

In several alternative embodiments, the sanitary napkin is comprised ofsome extensible components and some inextensible components. Forinstance, the sanitary napkin may have an extensible topsheet andbacksheet and an inextensible absorbent core that is slung between theextensible topsheet and backsheet. In a variation of such an embodiment,the sanitary napkin may have an inextensible topsheet as well.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming the subject matter which is regarded as formingthe present invention, it is believed that the invention will be betterunderstood from the following description which is taken in conjunctionwith the accompanying drawings (which are not necessarily to scale), inwhich like designations are used to designate substantially identicalelements, and in which:

FIG. 1 is a top plan view of a stretchable sanitary napkin according tothe present invention in unstretched condition.

FIG. 2 is a schematic sectional view taken along line 2--2 of thesanitary napkin shown in FIG. 1 in a disassembled condition.

FIG. 3 is a bottom plan view of the sanitary napkin shown in FIG. 1without the optional adhesive cover strip.

FIG. 4 is a top plan view taken which shows the sanitary napkin in FIG.1 after stretching. FIG. 5 is a top plan view of a stretchable sanitarynapkin which has optional side flaps and a topsheet fusion bonded to anunderlying component.

FIG. 6 is a simplified transverse cross-sectional view taken along line6--6 of FIG. 5.

FIG. 7 is a simplified transverse cross-sectional view similar to thatof FIG. 6, showing an alternate arrangement of the components of thesanitary napkin.

FIG. 8 is a table which shows the preferred relationship between themagnitude of stretching forces applied to the sanitary napkin and theamount the sanitary napkin stretches in response to such forces.

FIG. 8A is a plan view showing the extension of various portions of asanitary napkin in a wearer's panties.

FIG. 9 is a graph which illustrates the forces required to stretch asanitary napkin having a "force wall".

FIG. 10 is a schematic side view of one type of structure used to createa force wall.

FIG. 11 is a schematic side view of another type of structure used tocreate a force wall.

FIG. 12 is an edge view of an alternative topsheet that comprises anonwoven material and an apertured film.

FIG. 13 is a simplified schematic view of a topsheet material thatcomprises an apertured film with entangled nonwoven fibers.

FIG. 14 is a top plan view of a sanitary napkin having a topsheetcomprised of a nonwoven web with fibers generally oriented in thetransverse direction (only a portion of which are shown).

FIG. 15 is a photograph showing a cross-sectional view of an embodimenton which an underlying fibrous layer has been stretched and bonded to anapertured film.

FIG. 16 is a top plan view of a sanitary napkin having a topsheetcomprising an elastic scrim with fibers entangled with the scrim. (Thescrim is shown on a greatly enlarged scale, and only a portion of thescrim is shown.)

FIG. 17 shows a conventional process that could be used to cut a web ofstretchable material into individual topsheets, and a process forcreating a multi-directional stretch topsheet by cutting the web ofstretchable material fed into the process at an angle (or on a "bias" tothe machine direction).

FIG. 17A is a plan view of a film topsheet for a sanitary napkin thathas apertures that may provide the topsheet with extensibility.

FIG. 17B is a schematic plan view of a reversibly necked topsheetmaterial.

FIG. 18 is an exploded perspective view showing the assembly of astretchable sanitary napkin provided with a slit absorbent core.

FIG. 18A is a plan view showing a preferred glue pattern applied to theunderside of the topsheet of the sanitary napkin shown in FIG. 18.

FIG. 19 is a plan view of an absorbent core slit in the middle and notat the ends.

FIG. 20 is a plan view of an absorbent core provided with diamond-shapedapertures.

FIG. 21 is a top plan view of a thick sanitary napkin having a blendedcore and a profiled shape.

FIG. 22 is a simplified cross-sectional view of the sanitary napkin ofFIG. 21 taken along line 22--22.

FIG. 23 is a simplified cross-sectional view of the sanitary napkin ofFIG. 21 taken along line 23--23.

FIG. 23A is a schematic top plan view of a sanitary napkin formed withsome extensible components and some inextensible components.

FIG. 23B is a cross-sectional view of the sanitary napkin shown in FIG.23A.

FIG. 23C is a schematic cross-sectional view of another sanitary napkinformed with some extensible components and some inextensible components.

DETAILED DESCRIPTION OF THE INVENTION

1. Overall Characteristics of the Absorbent Article

The overall characteristics of the absorbent article of the presentinvention will be discussed first.

FIGS. 1-3 show a preferred embodiment of a disposable absorbent articleof the present invention. The present invention relates to absorbentarticles, such as sanitary napkins. More particularly, the presentinvention relates to thin sanitary napkins that are stretchable,especially in the longitudinal direction.

The term "absorbent article", as used herein, refers to articles whichabsorb and contain body exudates. More specifically, the term refers toarticles which are placed against or in proximity to the body of thewearer to absorb and contain the various exudates discharged from thebody. The term "absorbent article" is intended to include sanitarynapkins, pantiliners, and incontinent pads (and other articles worn inthe crotch region of a garment).

The term "disposable" refers to articles which are intended to bediscarded after a single use and preferably recycled, composted, orotherwise disposed of in an environmentally compatible manner. (That is,they are not intended to be laundered or otherwise restored or reused asan absorbent article.) In the preferred embodiment illustrated, theabsorbent article is a sanitary napkin designated 20.

The term "sanitary napkin", as used herein, refers to an article whichis worn by females adjacent to the pudendal region that is intended toabsorb and contain the various exudates which are discharged from thebody (e.g., blood, menses, and urine). The present invention, however,is not limited to the particular types or configurations of absorbentarticles shown in the drawings.

The sanitary napkin 20 has two surfaces, a liquid perviousbody-contacting surface or "body surface" 20A and a liquid imperviousgarment surface 20B. The sanitary napkin 20 is shown in FIG. 1 as viewedfrom its body surface 20A. The body surface 20A is intended to be wornadjacent to the body of the wearer. The garment surface 20B of thesanitary napkin 20 (shown in FIG. 2) is on the opposite side and isintended to be placed adjacent to the wearer's undergarments when thesanitary napkin 20 is worn.

The sanitary napkin 20 has two centerlines, a longitudinal centerline Land a transverse centerline T. The term "longitudinal", as used herein,refers to a line, axis or direction in the plane of the sanitary napkin20 that is generally aligned with (e.g., approximately parallel to) avertical plane which bisects a standing wearer into left and right bodyhalves when the sanitary napkin 20 is worn. The terms "transverse" or"lateral" used herein, are interchangeable, and refer to a line, axis ordirection which lies within the plane of the sanitary napkin 20 that isgenerally perpendicular to the longitudinal direction.

FIG. 1 shows that the sanitary napkin 20 also has two spaced apartlongitudinal edges 22 and two spaced apart transverse or end edges (or"ends") 24, which together form the periphery 26 of the sanitary napkin20. When the sanitary napkin 20 is worn, one of the end edges 24 will beoriented toward the front of the wearer, and one of the end edges 24will be oriented toward the rear of the wearer. The end edge 24 orientedtoward the front of the wearer is designated 24A, and the end edgeoriented toward the rear of the wearer is designated 248.

The sanitary napkin has two end regions, which are designated first endregion 28 and second end region 30. A central region 32 is disposedbetween the end regions 28 and 30. The end regions 28 and 30 extendoutwardly from the edges of the central region 32 about 1/8 to about 1/3of the length of the sanitary napkin. A detailed description of thecentral region 32 and the two end regions 28 and 30 is contained in U.S.Pat. No. 4,690,680 issued to Higgins on Sep. 1, 1987.

The sanitary napkin also has a longitudinally-oriented (or longitudinalcentral region 34 disposed along the length of at least a portion of thelongitudinal centerline L, and longitudinal side regions 36 laterallyoutboard of the longitudinal central region 34.

The sanitary napkin 20 can be of any thickness, including relativelythick, relatively thin, or even very thin. The embodiment of thesanitary napkin 20 shown in FIGS. 1-3 of the drawings is intended to bean example of a relatively thin sanitary napkin, preferably an"ultra-thin" sanitary napkin. It should be understood, however, whenviewing these figures the number of layers of material shown cause thesanitary napkin 20 to appear much thicker than it actually is. An"ultra-thin" sanitary napkin 20 preferably has a caliper of less thanabout 3 millimeters. The thin sanitary napkin 20 shown should also bepreferably relatively flexible, so that it is comfortable for thewearer.

FIG. 2 shows the individual components of the sanitary napkin. Thesanitary napkin 20 of the present invention generally comprises at leastfour primary components. These include a liquid pervious topsheet 38, aliquid impervious backsheet (or "barrier means") 40, an absorbent core42, and a fastener 44 for attaching the sanitary napkin to the wearer'spanties. The absorbent core 42 is positioned between the topsheet 38 andthe backsheet 40.

The sanitary napkin 20 of the present invention can also be providedwith any optional additional components. The optional components mayinclude, but are not limited to one or mere wicking layers 46 (such asthe aquisition layer or the "secondary topsheet" shown in FIG. 6), anoptional interliner 48 (FIG. 51), side flaps 52 (FIG. 5), and aremevable cover strip or release liner 50 (FIG. 2). The wicking layer 46may be positioned between the topsheet 38 and the absorbent core 42. Asshown in FIG. 51, the optional interliner 48 is positioned between theabsorbent core 42 and the backsheet 40. The side flaps or "wings" 52 arefolded around the crotch portion of the wearer's panties. (The wearer'spanties or undergarments are designated U in the drawings.) Theremovable release liner 50 covers the fasteners 44 when they compriseadhesives. This keeps the adhesives from sticking to surfaces other thanthe crotch portion of the undergarment prior to use of the sanitarynapkin 20.

The extensibility of the sanitary napkin 20 is shown in FIG. 4. The term"extensible", as used herein refers to articles that can increase in atleast one of their dimensions in the x-y plane. The x-y plane is a planegenerally parallel to the faces of the sanitary napkin 20. The termextensible includes articles that are stretchable and elasticallystretchable (defined below). The sanitary napkin 20 shown in FIG. 4 ispreferably extensible both in length and width. The sanitary napkin 20,in other embodiments however, may only be extensible in one of thesedirections. Preferably, the sanitary napkin 20 is extensible at least inthe longitudinal direction.

The sanitary napkin 20 may in some preferred embodiments, in addition tobeing extensible, also be stretchable. The term "stretchable", as usedherein, refers to articles that are extensible when stretching forcesare applied to the article and offer some resistance to stretching.

More preferably still, the sanitary napkin 20 may be elasticallystretchable. The terms "elastically stretchable" or "elasticallyextensible" are intended to be synonomous. These terms are illustratedin FIG. 4. These terms, used herein, mean that when the stretchingforces designated "F" are removed, the sanitary napkin will tend toreturn toward its unextended or unstretched dimensions (or "original"dimensions) L_(U) and W_(U). The sanitary napkin 20 need not return allthe way to its unstretched dimensions, however. It may, as shown in FIG.4, return to relaxed dimensions (such as L_(R) and W_(R)) between itsunstretched dimensions and extended (or stretched dimensions) L_(S) andW_(S).

Making the sanitary napkin elastically stretchable will reduce theundesirable tendency of the sanitary napkin to gather longitudinallyinward (i.e., bunch longitudinally) when forces which tend to stretchthe sanitary napkin are removed. This is particularly true when thewearer's panties contract.

2. Extensibility of Preferred Sanitary Napkin Embodiments

A. Introduction

The sanitary napkin 20 can be in the form of many different embodiments.

These embodiments may be placed into at least four general categoriesfor purposes of discussion. The first category deals with the type offorces used to extend the sanitary napkin. The first category iscomprised of two sub-categories: (a) sanitary napkins that depend onmanipulation by the user for their extensibility; and (b) sanitarynapkins that need only be subjected to the typical forces encounteredduring use for their extensibility. Both types of sanitary napkins arewithin the scope of the present invention.

A second category is based upon whether or not an appreciable amount offorce is required to extend the sanitary napkin. The sanitary napkinembodiments in the second category can be categorized as: (a) sanitarynapkins that require some appreciable amount of force to extend; and (b)sanitary napkins that can be extended with very little force. Both typesof sanitary napkins are within the scope of the present invention.

The third category relates to which components of the sanitary napkinare extensible. The sanitary napkin embodiments in the third categoryfall into two basic sub-categories: (a) sanitary napkins that arecomprised of all extensible components; and (b) sanitary napkins thatare comprised of some extensible components and some inextensiblecomponents. Examples of sanitary napkins in the second sub-categoryinclude, but are not limited to: (i) sanitary napkins having anextensible backsheet with an inextensible topsheet and absorbent core;and (ii) sanitary napkins having an extensible topsheet and backsheetthat form an extensible bag around an inextensible absorbent core.

The fourth category relates to whether the sanitary napkin is generallyextensible, or is generally inextensible and is associated with sometype of extensible element. The fourth category is comprised of at leasttwo sub-categories: (a) sanitary napkins that are provided withextensible components; and (b) sanitary napkins adapted to extend byassociating them with some type of extensible element. Examples of thesecond sub-category are sanitary napkins with extensible attachmentelements. Again, both types of sanitary napkins are within the scope ofthe present invention.

The categories may encompass subject matter that overlaps into othercategories. Other categories and sub-categories exist as well. Theoverall extensibility characteristics are described below. It should beunderstood, however, that the overall extensibility characteristics willoften depend on the sub-categories into which the sanitary napkin falls.

B. Extensibility Characteristics

(1) Amount of Extensibility

The sanitary napkin 20 is preferably capable of extending between about110% to about 150% of its unextended length (and its unextended width).(That is, the sanitary napkin is capable extending between about 10 or15% and about 50%.) More preferably, sanitary napkin 20 is capable ofextending between about 120% to about 140% of its unextended length (andwidth). In other embodiments, the sanitary napkin 20 (or portionsthereof) may be capable of extending greater or lesser amounts.

The amount of extensibility preferably corresponds to the amount thewearer's panties can stretch. In other words, during wear the sanitarynapkin 20 preferably extends about the same amount as the wearer'spanties. It has been found that 20% stretch is adequate to account formost stretch induced to the wearer's panties by body motions.

The forces required to extend the sanitary napkin and the otherparameters associated with the extensibility of some preferredembodiments of the sanitary napkin 20 are summarized in the table inFIG. 8. The forces and other parameters in Table 1 (as noted above) arethose associated with several preferred sanitary napkin embodiments.

It is to be understood that absorbent articles having parameters thatfall outside of those shown in Table 1 may also fall within the scope ofthe present invention in some circumstances. It is also to be understoodthat all of the limits and ranges specified herein include all narrowerranges and limits that are within the specified limits and ranges. Thus,for example, if a range is specified as being between about 125% andabout 150%, all narrower ranges, such as between about 130% and about140%, and between about 130% and about 150%, etc., may be claimed eventhough these limits and ranges are not separately listed. The forces aremeasured in accordance with the Test Methods described in Section 5 ofthis description.

The table first provides values for the forces required to extend thesanitary napkin in the longitudinal direction. The sanitary napkinshould preferably extend under the naturally occurring forces that causethe wearer's parities to stretch and move when the wearer moves. Thiswill allow the sanitary napkin to stretch with the wearer's panties. Thevalues in the table represent those forces.

The percentages of longitudinal extension provided above (and othermeasurements in Table 1) are measured along the longitudinal centerlineL of the sanitary napkin 20. Some portions of the sanitary napkin 20may, however, extend more (or develop a force wall after greaterextension) than the portions of the sanitary napkin that lie along thelongitudinal centerline L.

FIG. 8A shows that the portions of the sanitary napkin along thelongitudinal edges 22 of the sanitary napkin 20 may extend more than theportions lying along the longitudinal centerline L. In this embodiment,the panty fasteners 44 on the garment-facing side of the sanitary napkinare affixed closely to the leg elastics of the wearer's panties,particularly in the corner regions 27. This greater extension occurswhen the leg elastics of the wearer's panties stretch more than theportions of the panties underlying the longitudinal centerline of thesanitary napkin.

FIG. 8A shows that the portions of the sanitary napkin lying along thelongitudinal centerline L extend a distance "C". The portions of thesanitary napkin 20 lying along the longitudinal side edges 22 extend agreater distance "D". These portions of the sanitary napkin 20 lyingalong the longitudinal side edges 22 may extend up to 175%-200% of theirunextended length.

The table in FIG. 8 indicates that the sanitary napkin may also (oralternatively) be extensible in width. Further, FIG. 8 also indicatesthat the sanitary napkin may have an elastic "wall" (or "force wall")such that at a certain point, the forces required to further increasethe length and/or width of the sanitary napkin greatly increase. Theseparameters are discussed more fully below.

The portions of the sanitary napkin which are capable of extending theamounts described herein, should preferably contain some absorbentmaterial. The absorbent material is preferably capable of holding atleast about 0.05 gram of liquid per square cm. This is measured bydipping the absorbent material into distilled water, removing the samplefrom the water, and allowing the sample to drip for 30 seconds. Thisabsorbent material may be absorbent core material. Preferably, theabsorbent material that is capable of extending comprises more than asingle web of absorbent topsheet material.

An example of an embodiment which does not have absorbent materialcapable of extending is one in which the topsheet and backsheet extend(but are nonabsorbent), but the absorbent core does not. (Such anembodiment is not preferred because the extensible components do notinclude absorbent material. However, such a construction would stillprovide a degree of additional area coverage of the wearer's pantieswhen extended.)

(2) Force to Extend

The set of figures in the second column of Table 1 are the amounts offorce required to extend the sanitary napkin longitudinally. A set offigures is given for extending the sanitary napkin 25% and 40%.

The sanitary napkin will preferably extend at least 25% of its lengthunder forces of less than or equal to about 800 grams, preferably lessthan or equal to about 400 grams, and most preferably less than or equalto about 300 grams.

The sanitary napkin will preferably extend about 40 percent of itslength under forces of less than or equal to about 1250 grams. Morepreferably, the sanitary napkin will extend about 40 percent of itslength under forces of less than or equal to about 800 grams. Thesanitary napkin will (although not specified in Table 1) most preferablyextend about 40 percent of its length under forces of less than or equalto about 600 grams.

The set of figures in the third column of the table are the amounts offorce required to stretch the sanitary napkin across its width (in termsof the test described later which utilizes a 1.0 inch strip sample). Thetable is read in the same manner as for the longitudinal stretch.

The sanitary napkin 20 may be extensible only in length or width. Thesanitary napkin need not be extensible both longitudinally and in width.

There are also some embodiments of the sanitary napkin of the presentinvention that may not fall within the ranges in the table. Theseembodiments of the sanitary napkin may still within the scope of thepresent invention even though they may fall outside some of theparameters set out in the table.

(3) Minimum Force to Extend

A minimum force to extend the sanitary napkin any appreciable distance(e.g., 5%, or more preferably 10%) is desired so that the sanitarynapkin is easy to handle. A sanitary napkin with too low of a modulus ofelasticity (that is, one that stretches too easily) is difficult for theuser to handle and place into the panty. Such a sanitary napkin tends tobecome "stringy" similar to taffy.

Preferably, a force of at least about 50 grams is required for thesanitary napkin to extend about 25% and a force of at least about 100grams is required to extend the sanitary napkin about 40%. In morepreferred embodiments, a force of at least about 100 grams will berequired to extend the sanitary napkin about 25%.

(4) Force Wall

The sanitary napkin 20 preferably exhibits a stress-strain curve forlongitudinal or lateral extension similar to that shown in FIG. 9.

The sanitary napkin preferably extends relatively easily up to a desiredamount, then develops a force wall which prevents further extensionunder the forces normally encountered by the sanitary napkin during useand removal.

The sanitary napkin need not have a force wall in all embodiments.Further, in embodiments where a force wall is provided, the force wallmay only be provided to prevent further increases in the length or widthof the sanitary napkin.

Typically, it is more important to provide a force wall to preventfurther increases in length. This is because the sanitary napkin may besubjected to the greatest stretching forces along its length.

The sanitary napkin is subjected to relatively large stretching forcesin the longitudinal direction during removal of the napkin from thewearer's panties. A force wall prevents the sanitary napkin fromstretching excessively during removal of the sanitary napkin from thewearer's panties. In addition, a force wall may be desirable since thelength of the sanitary napkin is greater than its width, and, therefore,the sanitary napkin is capable of stretching a greater amount in thelongitudinal direction than in the transverse direction.

Such a force wall may include, but is not limited to those which areintrinsic in the materials used in the components of the sanitary napkin20 and those created as a result of its construction where mechanical"stops" are placed into the sanitary napkin to prevent extension beyonda certain point.

The first type of force wall can, for example, be seen in a hypotheticalfilm. The film may produce a force wall when stretched to a certainlimit. For instance, the film may extend about 10% (i.e., 110% of itsoriginal dimensions) before reaching a point where it cannot bestretched further without substantial force. Typically, however, thefilm will have to be subjected to forces in excess of those desiredherein to achieve this initial 10% extension unless it is madeextensible as described herein.

FIG. 10 shows an example of a mechanical "stop" 54. The schematicdrawing depicts an extensible component 56. The extensible component 56could, as a non-limiting example, comprise an extensible absorbent coreor an extensible backsheet. The extensible component 56 has either aninextensible or less extensible restraining element 58 attached to it.The restraining element 58 is attached so that it is provided with slackor flaccid material which allows the core or backsheet to extend to aspecified length, but no further without an appreciable amount of force.

FIG. 11 shows an example of a laminate structure that can be used toprovide the sanitary napkin with a stop or force wall. The example showncould represent the backsheet. The backsheet 40 could be a laminatecomprised of a stretch laminate film, such as stretchable adhesive film60 laminated to a pre-stretched polyethylene film 62. The two films arelaminated together when the pre-stretched film 62 is relaxed. When thebacksheet 40 is stretched, it will easily stretch up to thepre-stretched length of the polyethylene film 62, but will extend nofurther without substantial force.

The laminate structures that are used to provide the sanitary napkinwith a stop or force wall need not be bonded across the entire interfacebetween the component parts of the laminate.

For example, a laminate could be formed of a pre-stretched material,such as an elastic film and an absorbent material. The absorbentmaterial could be intermittently bonded to the pre-stretched film whenthe film is in its stretched condition. The two components could bebonded at a plurality of lines, spots, or other locations. Thecomponents could be bonded by glue, thermal bonds, or any other suitabletype of bond.

The resulting laminate will form puckered areas when it is relaxed. Itcan have unidirectional stretch, bi-directional stretch, ormulti-directional stretch. The laminate will be able to extend to thepre-stretched dimensions of the elastic film, but will extend no fartherwithout substantial force. The laminate thus formed could be used as acombination structure that serves as one or more of the basic componentsof the sanitary napkin.

(5) Amount of Recovery (or Percent Set)

The amount of recovery of the sanitary napkin can vary in differentembodiments. Thus, upon extension to 125% or to 140% of its originallength, the sanitary napkin need not return to its original length whenthe extending load is released. However, it is preferable if thesanitary napkin returns to less than 110% of its original length so thatwhen the sanitary napkin extends, it will return as the panty materialrelaxes and/or the wearer's body moves, and will not bunch. Table 1shows that in less preferred embodiments, the sanitary napkin may returnto up to less than or equal to 125% of its original length when theextending load is released.

(6) Rate of recovery

If the sanitary napkin has the capability of recovering toward itsunstretched dimensions, it preferably has a relatively low rate ofrecovery. A relatively low rate of recovery is desirable for severalreasons.

The sanitary napkin will fit best against the wearer's body when itslowly returns toward its unextended dimensions after it is stretched.The sanitary napkin can be gently held against the wearer's body and inconformity therewith by the forces that tend to return the sanitarynapkin toward its unextended dimensions. The sanitary napkin can alsohave regions that, due to creep of the same, may not tend to returntoward their original dimensions. These regions may also aid body fit.Thus, the sanitary napkin can be contrasted with conventional elasticmaterials such as LYCRA that have substantial tendencies to retract.

A rapid recovery rate also makes the sanitary napkin undesirable from aconsumer viewpoint in removing the sanitary napkin from the panty. Afteruse, the user will often rip the sanitary napkin out of the crotchregion of her panties in a fairly aggressive manner. If the rate ofrecovery is too high, the sanitary napkin may tend to snap back towardthe user during removal (i.e., like a rubber band). This is particularlyimportant when the longitudinal extension of the sanitary napkin isgreater than or equal to about 20%.

The rate of recovery should be high enough, however, so the sanitarynapkin will return to its recovered length or width within a few seconds(i.e., less than or equal to about 5 seconds).

Preferably, the sanitary napkin will return to its recovered length orwidth at a rate in the range of about 0.5 inches/sec. (about 1.3cm./sec.) to about 2 inches/sec. (about 5 cm./sec.).

3. The Individual Components of the Sanitary Napkin

The individual components which may be suitable for various embodimentsof the sanitary napkin 20 of the present invention will now be looked atin greater detail with reference to FIGS. 1-3.

A. The Topsheet

(1) General Characteristics of Preferred Topsheet Material

The topsheet 38 comprises a first liquid pervious component. When thesanitary napkin 20 is in use, the topsheet 38 is in close proximity tothe skin of the user. The topsheet 38 is preferably as compliant, softfeeling, and non-irritating to the user's skin as possible. The topsheet38 should further exhibit good strikethrough and a reduced tendency tofewer, permitting bodily discharges to rapidly penetrate it and flowtoward the core 42, but not allowing such discharges to flow backthrough the topsheet 38 to the skin of the wearer.

The topsheet 38 has two sides (or faces or surfaces), including abody-facing side 38A and a garment-facing side (or core-facing side)38B. The body-facing side 38A of the topsheet generally forms at least aportion of the body-contacting surface ("body surface") 20A of thesanitary napkin 20. The topsheet 38 has two longitudinal edges 38C andtwo end edges 38D.

(A similar numbering system will be used for the other components of thesanitary napkin. That is, the side of the component facing the wearer'sbody will be designated by the number of the component and a referenceletter "A". The side facing the wearer's undergarments will bedesignated by the number of the component and the letter "B". The sideand end edges will be designated by the number of the component and thereference letters "C" and "D" respectively.)

A suitable topsheet 38 may be manufactured from a wide range ofmaterials including, but not limited to woven and nonwoven materials,apertured formed thermoplastic films, apertured plastic films,hydro-formed films, porous foams, reticulated foams, reticulatedthermoplastic films, and thermoplastic scrims.

Suitable woven and nonwoven materials can be comprised of natural fibers(e.g., wood or cotton fibers), synthetic or modified natural fibers(e.g., polymeric fibers, such as polyester, polypropylene fibers, andpolyethylene, or polyvinylalcohol, starch base resins, polyurethanes,cellulose esters, nylon, and rayon fibers) or from a combination ofnatural and synthetic fibers.

When the topsheet 38 comprises a nonwoven web, the web may bespunbonded, carded, wet-laid, meltblown, hydroentangled, combinations ofthe above, or the like.

Apertured films are generally preferred for the topsheet 38 because theyare pervious to liquids and, if properly apertured, have a reducedtendency to allow liquids to pass back through and rewet the wearer'sskin. Suitable apertured films can be made of any of the materialsspecified in the publications that describe films and methods of makingfilms which are incorporated by reference herein.

Suitable films are described in U.S. Pat. No. 3,929,135 issued toThompson on Dec. 30, 1975, U.S. Pat. No. 4,324,426 issued to Mullane etal. on Apr. 13, 1982, U.S. Pat. No. 4,342,314 issued to Radel et al. onAug. 3, 1982, U.S. Pat. No. 4,463,045 issued to Ahr, et al. on Jul. 31,1984, and U.S. Pat. No. 5,006,394 issued to Baird on Apr. 9, 1991.Additional suitable formed and hydro-formed films are described in U.S.Pat. Nos. 4,609,518, 4,629,643, 4,695,422, 4,772,444, 4,778,644, and4,839,216 issued to Curro, et al., and in U.S. Pat. No. 4,637,819 issuedto Ouellette, et al.

Still other materials suitable for use as a topsheet are described inU.S. Pat. No. 4,775,579 issued to Hagy, et al. on Oct. 4, 1988, U.S.Pat. No. 4,798,604 issued to Carter on Jan. 17, 1989, U.S. Pat. No.5,023,124 issued to Kobayashi on Jun. 11, 1991, and in European PatentApplication 0 304 617 A2 published Mar. 1, 1989 in the name of Suda, etal.

In still other embodiments, the materials described in some of the abovereferences (such as the stretchable polymeric materials described inU.S. Pat. No. 4,798,604 issued to Carter) could be made into the filmsdescribed in other references. For instance, the stretchable polymericmaterials described in U.S. Pat. No. 4,798,604 could be made into themacroscopically expanded three dimensional plastic film having asubstantially non-glossy surface described in U.S. Pat. No. 4,463,045.

In another embodiment shown in FIG. 12, the topsheet 38 could comprise astructure comprising a nonwoven material or fabric 64 and an aperturedfilm such as three dimensional apertured plastic film 66. The nonwovenmaterial provides the topsheet with an improved, less plastic-like feel.

In one preferred version of the embodiment shown in FIG. 12, thenonwoven material 64 has a basis weight from about 1 to about 40 g/sq.m., more preferably from about 8 to about 12 g/sq. m. One preferrednonwoven material comprises a carded thermally dot bonded polypropyleneweb. Some preferred nonwoven fabrics are manufactured by the FiberwebGroup of Simpsonville, S.C. under the trademarks CELESTRA and HOLMESTRA.

The plastic film 66 is a thermoplastic material provided with amultiplicity of tapered capillaries 39 in a manner, size, configuration,and orientation set forth in U.S. Pat. No. 3,939,135 issued to Thompson.The film is treated with a surfactant such as ATMER 645 manufactured byICI Specialty Chemicals. Preferably, the surfactant is incorporated intothe polyolefin resin pellets from which the film is made.

The nonwoven fabric 64 and the apertured plastic film 66 may beintegrally formed into a composite structure such as that shown in FIG.12 by embedding the fibers of the nonwoven material into thethermoplastic film when the latter is in a molten condition using avacuum lamination process. Such a topsheet is described in greaterdetail in U.S. patent application Ser. No. 07/794,745 filed by Aziz, etal. on Nov. 19, 1991. In alternative embodiments, the nonwoven fabricand the film may be placed into a face-to-face relationship. The twocomponents are preferably secured to each other in these latterembodiments. Suitable methods for securing the two components include,but are not limited to adhesives, fusion including heat bonding and/orpressure bonding, ultrasonics, and dynamic mechanical bonding.

FIG. 13 shows that in still other embodiments, the topsheet 38 maycomprise a fiber-entangled film. The term "fiber-entangled film" refersto apertured films having fibers entangled in and around theirapertures.

The apertured film 68 of such a topsheet could comprise any of the filmsor scrims described herein. One particularly suitable apertured film 68for use in such a topsheet is disclosed in U.S. Pat. No. 4,463,045 andring-rolled (as described below) to provide it with a degree ofextensibility. The film 68 can be ring rolled before or after theentanglement of the fibers.

The film 68 has nonwoven fibers 70 loosely mechanically orthermo-mechanically entangled therewith. The fibers 70 are preferablyentangled along or from the direction of either the body-facing side38A, or the core-facing side 38B.

The fibers 70 could be mechanically or thermo-mechanically entangledwith the film 68 by any suitable process. For instance, the fibers 70could be meltblown onto the film, spunbonded onto the film, carded ontothe film, thermo-mechanically entangled with the film such as beingflocked or meltblown on the plastic film while the film is still in itsmolten state, or hydro-entangled with the film. One suitable meltblowingprocess is disclosed in Exxon U.S. Pat. No. 3,978,185 issued to Buntin,et al.

The fibers 70 may be either hydrophilic or hydrophobic. Suitablehydrophilic fibers may be formed from intrinsically wettable fibers suchas nylon co-polymers comprising a nylon component and a hydrophilizingcomponent. Such a material is commercially available from Allied SignalInc. under the trade designation Hydrofil SCFX.

In a preferred embodiment, the fibers 70 are of a thermoplasticsynthetic nature. Suitable polyethylene fibers are available from theDow Chemical Company under the trade designation ASPUN, andpolypropylene fibers are available from the Exxon Corporation under thetrade name ESCORENE 3,400 and 3,500 series.

Once formed, the fiber-entangled film structure is preferably treated byany known methods to render it hydrophilic. Such process will allow theapertures 39 of the film to better handle liquids. The compositestructure may be ring-rolled after these treatment processes.

The fiber-entangled topsheet 38 material provides more intimate contactbetween the apertured film 68 and the nonwoven fibers 70. This cancreate advantages of improved liquid transport through the film 68 tothe fibers 70 and the underlying layers. It may also provide improvedcomfort if the fibers lie along the body-facing side 38A of the topsheet38. It can also provide improved comfort when fibers lie along thecore-facing side 38B of the topsheet 38 since the film 68 portion of thetopsheet 38 will be less likely to separate from the underlyingentangled fibers 70 and move into the crevices of the wearer's body.

(2) Alternative Ways of Providing the Topsheet With Extendibility

There are several basic ways of providing the topsheet materialsdescribed above with extensibility. A non-limiting number of these waysare described below.

One way of making the topsheet 38 extensible is by performing amechanical operation, such as pleating, corrugating, or ring rolling onthe topsheet material to provide folds in the topsheet that are able toopen when the topsheet is stretched. Such a process can be performed onmany of the topsheet materials described above.

In one preferred embodiment of the present invention, the topsheet 38 ismade in accordance with U.S. Pat. No. 4,463,045 and ring rolled toprovide it with a degree of longitudinal extensibility.

Such a topsheet is described in the following patent applications whichwere filed on Jul. 23, 1991: U.S. patent application Ser. No. 07/734,404filed in the names of Thompson, et al.; U.S. patent application Ser. No.07/734,392 filed in the names of Thompson, et al.; and, U.S. patentapplication Ser. No. 07/734,405 filed in the names of Buenger, et al.These patent applications may be referred to collectively as the"Capillary Channel Fiber" patent applications.

Suitable processes for ring rolling or "pre-corrugating" are describedin U.S. Pat. No. 4,107,364 issued to Sisson on Aug. 15, 1978, U.S. Pat.No. 4,834,741 issued to Sabee on May 30, 1989 and in co-pending,commonly assigned U.S. patent application Ser. No. 07/662,536 filed byGerald M. Weber et al. on Feb. 28, 1991, U.S. patent application Ser.No. 07/662,537 filed by Kenneth B. Buell et al. on Feb. 28, 1991, andU.S. patent application Ser. No. 07/662,543 filed by Gerald M. Weber etal. on Feb. 28, 1991 (collectively referred to herein as the "RingRolling" patent applications).

The fold lines in the corrugations of a ring rolled topsheet should runin the transverse direction so the topsheet is longitudinallyextensible. In other embodiments, the fold lines could run in thelongitudinal direction, both directions, and/or other directions. Thetopsheet 38 will be extensible in directions perpendicular to the foldlines.

FIG. 14 shows that in other embodiments, the topsheet 38 could becomprised of a nonwoven material having fibers 78 generally oriented ina direction perpendicular to the direction of the desired stretch. Thetopsheet, for instance, could be comprised of fibers generally orientedin the transverse direction to provide extensibility in the longitudinaldirection.

FIG. 15 shows another alternative topsheet embodiment. In FIG. 15, thetopsheet 38 is bonded to an underlying acquisition layer 46 by the typeof individual fusion bonds 72 shown in FIG. 5. In the embodiment shownin FIG. 15, the acquisition layer 46 is stretched before it is fused tothe topsheet 38. The topsheet 38 and acquisition layer 46, thus, form alaminate. When the stretched laminate is relaxed, the laminate hastufted areas 74 formed therein between bonded areas 72 and valleys 76formed at the bonds.

The embodiment shown in FIG. 15 provides a key advantage. It (and itsvarious alternative embodiments) allows a stretchable laminate to beformed from materials that are not ordinarily thought of as beingstretchable. The apertured plastic film topsheet 38, for instance, isnot normally thought of as being extensible. However, the topsheet 38 isprovided with a degree of extensibility when it is secured to a layersuch as the acquisition layer 46 after the acquisition layer 46 has beenextended and the two component materials are thereafter relaxed.

The tufted areas 74 in such a laminate can also provide certainbenefits. The tufted areas 74 are typically soft. They will also placethe absorptive fibers of the acquisition layer 46 closer to the wearer'sbody than the nontufted bonded areas. This construction may also enhanceabsorption (particularly at the tufted areas 74).

In other alternative embodiments, both the topsheet 3B and theacquisition layer 46 can be stretched prior to fusing the same together.

In other embodiments, the topsheet 38 can be made extensible by formingit from extensible, or more preferably, stretchable materials. Thetopsheet 38 can, for instance, be an apertured film made of apolyethylene/Kraton blend such as Exxon film EXX-7 available from theExxon Corporation. This will yield a stretchable material without anymechanical manipulation.

In other embodiments, the topsheet materials tan include low basisweight nonwovens (nonwoven materials having a basis weight from about 18to about 25 grams per square meter). An example of such a nonwovenmaterial is manufactured by Veratec, Inc., a Division of InternationalPaper Company, of Walpole, Mass. under the designation P-8.

In other embodiments, the topsheet could be comprised of a thermo-formedmass of fibers or hydroentangled nonwovens.

FIG. 16 shows that in still other embodiments, the topsheet 38 couldhave elastic structural components. One example of such a structure is anet, screen, or scrim 80 comprised of elastic ribs 82. An example ofsuch a structure is disclosed in U.S. Pat. No. 4,062,995 issued toKorpman Dec. 13, 1977. The net could have square-shaped ordiamond-shaped apertures 84 between its ribs. Such a structure isgenerally stretchable in all directions. Elastic or inelastic fibers 86could be added or adhered to the net.

The topsheet 38 can, in still other alternative embodiments, bemanufactured into a structure that is capable of stretching in more thanone direction from materials that are only capable of stretching in onedirection.

FIG. 17 shows an example of a process that can be used for this purpose.The left side of FIG. 17 shows a conventional process that could be usedfor cutting a web of stretchable material 88 into individual topsheets38. The web 88 runs in the machine direction (MD). This is also thedirection the web 88 stretches.

The right side of FIG. 17 shows a process of creating amulti-directional stretch topsheet by cutting the web of stretchablematerial at an angle (or on a "bias" to the machine direction). In avariation of this process, the web could be fed in at an angle and cutin the same direction as shown in the conventional process. Theresulting cut topsheet 3B will be able to stretch in two directions asshown by the arrows near the cut topsheets.

FIG. 17A shows that in still other embodiments, an apertured filmtopsheet 38 can be provided with apertures 39 having a geometry that isconducive to allowing the topsheet 38 to stretch in a particulardirection.

In still other embodiments, the topsheet 38 could be slit forextensibility as described below for the absorbent core.

In still other embodiments (shown in FIG. 17B), the topsheet 38 cancomprise a reversibly necked material. Reversibly necked materialsgenerally comprise materials that increase in width (rather thandecrease) when extended longitudinally. Such materials are useful insanitary napkins because they ire not subject to the reduction in theirability to cover a given area of the crotch of the wearer's panties whenthe sanitary napkin is stretched. In fact, their ability to cover thecrotch area will increase when they are stretched. As shown in FIG. 17B,if this increase in width is great enough, these materials can be usedto form flap-like structures when the sanitary napkin is stretched.

One suitable way of creating a reversibly necked material is describedin U.S. Pat. No. 4,965,122 issued Oct. 23, 1990 to Morman.

(3) Additional Steps

In addition to the above, in preferred embodiments of the presentinvention, at least a portion of the topsheet 38 is treated with asurfactant. This can be accomplished by any of the common techniqueswell known to those skilled in the art.

Suitable methods for treating the topsheet 38 with a surfactant aredescribed in a number of references, including U.S. Pat. Nos. 4,950,264and 5,009,653 issued to Osborn, and in U.S. patent application Ser. No.07/794,745 filed by Aziz, et al. on Nov. 19, 1991. The latter patentapplication teaches treating the apertured film component of anonwoven/apertured thermoplastic formed film topsheet with a surfactant.The surfactant is preferably incorporated into the resin used to makethe thermoplastic formed film.

Treating the topsheet 38 with a surfactant renders the topsheet 38 morehydrophilic. This results in liquid penetrating the topsheet 38 fasterthan it would if the surface were not treated. This diminishes thelikelihood that body fluids will flow off topsheet 38 rather than beingdrained through the topsheet 38.

In addition, in preferred embodiments, the inner surface 388 of topsheet38 is secured in contacting relation with an underlying absorbent layer.This contacting relationship results in liquid penetrating topsheet 38faster than if the topsheet 38 were not in contact an absorbentcomponent. However, it is not absolutely necessary to bond the face ofthe topsheet 38 to the face of the underlying layer.

The topsheet 38 can be maintained in contact with an underlyingabsorbent component by applying adhesives between the topsheet and theunderlying component, by entangling the fibers of the underlying layerwith the topsheet, by fusing the topsheet 38 to an underlying absorbentlayer by a plurality of discrete individual fusion bonds, or by anymeans known in the art.

FIGS. 5 and 7 show a preferred type of fusion bond which forms bondedareas which provide structures with drainage passageways for liquids topass through to the underlying absorbent material. These preferredfusion bonds are described in greater detail in U.S. patent applicationSer. No. 07/810,774 filed in the names of Cree, et al. on Dec. 17, 1991.

B. The Absorbent Core

(1) General Characteristics of Preferred Absorbent Core Structures

The absorbent core 42 is positioned between the topsheet 38 and thebacksheet 40. The absorbent core 42 provides the means for absorbingmenses and other body fluids.

The absorbent core 42 need not have an absorbent capacity much greaterthan the total amount of fluid anticipated to be absorbed, The absorbentcore 42 is generally compressible, conformable, and non-irritating tothe user's skin. It can comprise any material used in the art for suchpurpose. Non-limiting examples include natural materials such ascomminuted wood pulp which is generally referred to as airfelt, crepedcellulose wadding, hydrogel-forming polymer gelling agents, modifiedcross-linked cellulose fibers (described below), capillary channelfibers, absorbent foams, absorbent sponges, synthetic staple fibers,polymeric fibers, peat moss, or any equivalent material or combinationsof materials.

The polymeric gelling agents listed above may also be referred to as"absorbent gelling materials" or "superabsorbent materials". Polymericgelling agents are those materials which, upon contact with liquids suchas water or other body liquids, imbibe such liquids and thereby formhydrogels. In this manner, liquids discharged into the absorbent core 42can be acquired and held by the polymeric gelling agent, therebyproviding the articles herein with enhanced absorbent capacity and/orimproved liquid retention performance.

The polymeric gelling agent which is employed in the absorbent core 42will generally comprise particles 41 of a substantially water-insoluble,slightly cross-linked, partially neutralized, hydrogel-forming polymermaterial. The term "particles", as used herein, can refer to particlesin any form, such as in the form of pellets, flakes, or fibers.

The general characteristics of one basic type of absorbent core 42(including, but not limited to the preferred types of polymer materialsused therein, and types of methods which can be used for preparing thesepolymer particles) are described in greater detail in U.S. Pat. No.5,009,653 issued to Osborn and the patents incorporated by reference inthat patent, the disclosures of which are all incorporated by referenceherein. (The absorbent cores 42 described herein need not includesuperabsorbent material particles, however.)

Suitable cross-linked cellulose fibers for the absorbent core aredescribed in U.S. Pat. No. 4,888,093, issued Dec. 19, 1989 to Cook, etal.; U.S. Pat. No. 4,822,543, issued Apr. 18, 1989 to Dean, et al.; U.S.Pat. No. 4,889,595, issued Dec. 26, 1989 to Schoggen, et al.; U.S. Pat.No. 4,898,642, issued Feb. 6, 1990 to Moore, et al.; and U.S. Pat. No.4,935,022 issued Jun. 19, 1990 to Lash et al.; EPO Patent ApplicationPublication Nos. 0 427 316 A2 and 0 427 317 A2 published in the name ofHerron, et al. on May 15, 1991; and EPO Patent Application PublicationNo. 0 429 112 A2 published in the name of Herron, et al. on May 29,1991.

Suitable capillary channel fibers (that is, fibers having channelsformed therein, preferably, on their exterior surfaces) for theabsorbent core are described in greater detail in the Examples providedbelow, in EPO Patent Application 0 391,814 published Oct. 10, 1990, andin the aforementioned Capillary Channel Fiber patent applications.

Suitable absorbent cores comprising foams are described in U.S. patentapplication Ser. Nos. 07/743,839, 07/743,950, 07/743,947, and 07/830,159(P&G Case Nos. 4451, 4452, 4453, and 4453R) The first, third and fourthapplications listed were filed in the names of DesMarais, et al. Thesecond application listed was filed in the name of Young, et al. Thefirst three applications were filed on Aug. 12, 1991, and the fourth onFeb. 12, 1992. Additional cores comprising foams are described inEuropean Patent Application 0 293 208 B1.

Absorbent cores comprising sponges are described in U.S. Pat. Nos.3,512,530, 3,954,493 and French Patent 2,203,827.

Additional suitable absorbent cores that can be provided withextensibility are described in the following references: U.S. Pat. Nos.4,773,903 and 4,865,596 issued to Weisman, et al. on Sep. 27, 1988 andSep. 12, 1989, respectively. These patents disclose composite absorbentstructures comprising webs of entangled blown microfibers, substantiallynonabsorbent crimped staple fibers, particles of hydrogel-formingpolymeric gelling agents and a hydrophilizing agent.

Other suitable absorbent core materials comprise mixtures of melt blownelastic fibers and absorbent materials. One such core material comprisesa hydro-entangled composite of cotton and melt blown fibers known asproduct #7102-102 available from Fiberweb of Simpsonville, S.C. In otherembodiments, the cotton could be replaced with other absorbent materialssuch as FSA fiber Type 101 or 102 available from Courtaulds Fibers, Ltd.West Midlands, England. Alternatively, two plies of a material such asthe above product #7102-102 could be laminated together with aparticulate polymeric gelling agent in between and provided withextensibility to produce a highly absorbent extensible laminate.

In addition, the absorbent core 42 can be comprised of many materialsdescribed herein as being suitable for use as topsheets. In order to besuitable, however, these materials must be absorbent or used inconjunction with some absorbent material. For instance, the absorbentcore 42 could be comprised of a structure similar to the elastic scrimshown in FIG. 16 with absorbent fibers adhered thereto.

(2) Providing the Absorbent Core With Extensibility

There are many possible extensible absorbent core embodiments. Theseinclude, but are not limited to the embodiments described below. Thecomponents of the embodiments described below can also be combined inany suitable manner to form additional embodiments.

(a) Laminates

In one preferred embodiment shown in FIG. 2, the absorbent core 42 is alaminate. The laminate is comprised of a layer of superabsorbent polymermaterial, such as in the form of particles 41, disposed between twoair-laid tissues, first and second tissue layers (or "upper" and "lower"tissue layers) 43 and 47, respectively.

The first and second tissue layers 43 and 47 provide containment of thesuperabsorbent polymer material, improve lateral wicking of the absorbedexudates throughout the absorbent core 42 and provide a degree ofabsorbency. The tissue layers 43 and 47 can be comprised of a singletissue web which is folded with the superabsorbent material particles 41between, or two separate sheets of the same (or different) tissue.

A suitable laminate is a superabsorbent laminate known as WATER-LOCKL-535 available from the Grain Processing Corporation of Muscatine, Iowa(WATER-LOCK registered TM by Grain Processing Corporation). Suchsuperabsorbent laminates are disclosed in U.S. Pat. No. 4,467,012,issued to Pedersen et al. on Aug. 21, 1984, U.S. Pat. No. 4,260,443,issued to Lindsay et al. on Apr. 7, 1981, and U.S. Pat. No. 4,578,068issued to Kramer, et al. on Mar. 25, 1986.

The laminate absorbent core 42 can be made extensible by making the samefrom tissue paper having between 20% and 200% stretch (i.e., capable ofextending between about 120% and 300% of its original length). Suchtissue sheets can be made by a number of processes. The tissue paper mayin one embodiment, be conventionally creped tissue. For example, thetissue paper may be a BOUNTY tissue that is run through a crepingprocess.

In other embodiments, the tissue may be made by a suitable variation ofthe process described in U.S. Pat. No. 4,191,609 issued to Trokhan onMar. 4, 1980, or by a suitable variation of the processes described inU.S. Pat. No. 4,529,480 issued to Trokhan on Jul. 16, 1985, or theprocesses described in European Patent Application Publication Nos. WO92/00414, WO 92/00415, and WO 92/00416 published Jan. 9, 1992. In thelatter cases, the tissue may be made extensible by one or more of thefollowing procedures: adjusting the angle of the doctor blade to provideadditional creping; tailoring the characteristics of the paper's networkregion to allow a certain amount of stretch; or, by removing the paperweb from the Yankee dryer earlier than ordinary before it is subjectedto further drying to give it a creped effect.

In alternative embodiments, a tissue with no or very low initial crepecan be creped after lamination. The creping process in this case couldoccur by passing the laminate through two matched rolls such that theywould yield a corrugated laminate tissue with stretch in the range of20% to 200% (capable of extending between about 120% and 300% of itsoriginal length). The corrugations should be perpendicular to thedirection of desired stretch.

In a related alternative embodiment, the laminate could be creped byadhering the laminate to a surface and creping the laminate off thesurface. This could be done in a manner similar to the step of removingthe paper web from a Yankee dryer described in the aforementioned EPOpatent applications.

In another related embodiment, the laminate could be creped by pressinga pattern into it while the laminate is on a flat surface. For instance,a pair of flat plates could be used to impress a pattern into thelaminate similar to that shown in U.S. Pat. No. 4,578,068 issued toKramer, et al.

In alternative embodiments, the laminate can be cut or slit to providean extensible absorbent core structure. FIG. 18 shows that in aparticularly preferred embodiment, the absorbent core 42 is a laminateas described above which is slitted or partially slitted forlongitudinal extensibility. FIG. 19 shows an alternate absorbent corethat is slit at the central region, and not at the end regions. FIG. 20shows an alternate absorbent core that has diamond-shaped apertures cuttherein. Any other suitable shape or shapes of apertures can be used.

Other types of slit absorbent materials are described in European PatentApplication Publication Number 0 293 208 B1 published by LionCorporation on Jul. 24, 1991.

The longitudinal and end edges 22 and 24 of the sanitary napkin 20 arepreferably sealed to prevent the wicking and expulsion of liquid orliquid-containing superabsorbent material from the napkin when it isextended. Alternatively, the edges 42C and 42D of the absorbent core 42may be sealed rather than sealing the edges of the entire sanitarynapkin. The edges of the core 42 may, for example, be wrapped or coveredby a tissue layer. In other alternative embodiments, the edges of thetissue may be folded, or otherwise manipulated to prevent the wickingand expulsion of liquid or liquid-containing superabsorbent materialparticles 41 from the core 42. All permanent seals around the perimeterof the sanitary napkin 20 should not break upon lengthening (i.e., anyseal is intended to remain for the duration of the use of the sanitarynapkin.)

In any of the laminate absorbent core embodiments described above, asheet of other any other known absorbent materials including, but notlimited to peat moss, modified cross-linked cellulose fibers, orsynthetic fibers could replace the cellulose fibers in one or more ofthe tissue layers. The basis weights of the tissue layers could also bevaried between layers.

(b) Structures Containing Mixtures of Absorbent Materials andSuperabsorbent Materials

The absorbent core 42 could, instead of comprising a laminate structure,be comprised of a mixture of the absorbent materials and superabsorbentmaterials described above.

For example, mixtures of superabsorbent materials with airfelt, modifiedcross-linked cellulose fibers cross-linked carboxy methyl cellulose suchas that described in U.S. Pat. No. 4,475,911 issued to Gellert on Oct.9, 1984, peat moss, or other absorbent materials can be used to makethin webs. These thin webs may then be creped, ring-rolled, slit, orotherwise manipulated as described herein to produce an extensibleabsorbent core 42.

The superabsorbent material particles 41 can be distributed in any knownmanner tn any of the embodiments described herein. The superabsorbentmaterial particles 41 may be homogeneously blended with the absorbentmaterials described herein. In other embodiments, the superabsorbentmaterial particles can be distributed tn a superabsorbent materialconcentration gradient in the sanitary napkin. Known manners forestablishing such a concentration gradient are described in EuropeanPatent Application No. 0 198 683 published Oct. 22, 1986 in the name ofDuenk, et al., U.S. Pat. No. 4,699,823 issued Oct. 13, 1987 toKellenberger, et al. and U.S. Pat. No. 5,009,650 issued to Bernardin onApr. 23, 1991.

(c) Structures Containing Mixtures of Various Types of Fibers

The absorbent core 42 can comprise a mixture of various types of naturalor synthetic fibers and particular superabsorbent materials.

(i) The "Blended" Core

FIGS. 21-23 show one particularly preferred absorbent core 42 that willbe referred to as a "blended" core. This particular core arrangement isshown in a relatively thick sanitary napkin 20. It can, however, also beformed into a thin web for use in thin products.

The blended absorbent core 42 comprises a batt of fibers, preferably inthe form of a homogeneous blend of fibers. The blended core 42 iscomprised of at least two groups (or types) of fibers. These include afirst group (or type) of low denier, relatively short, hydrophilicfibers, and from about 5% to about 90% of higher denier (and ispreferably about 10%), longer synthetic fibers that comprise a secondgroup (or type) of fibers. The blend ratio of the two groups of fiberscan be varied to produce the properties desired for different types ofabsorbent articles. (All percentages specified in this description areby weight unless stated otherwise.)

The first group of fibers can comprise natural fibers such as cotton,cellulose, or other natural fibers. The first group of fibers canalternatively or additionally comprise synthetic fibers such assuperabsorbent material fibers and capillary channel fibers,mechanically or chemically modified natural fibers, including but notlimited to, rayon, chemical thermal mechanical pulp (or "CTMP" or"TMP"), ground wood, or cross-linked cellulose fibers. For oneembodiment, the first group of fibers comprises airfelt. The fibers inthe first group of fibers are either inherently hydrophilic, or they maybe rendered hydrophilic by treating them in any of the manners describedpreviously to render them hydrophilic.

Performance is improved by selecting a relatively stiff fiber whichmaintains a substantial portion of its compression resistance whenwetted. (That is, the fibers should have a high compressive modulus.)Preferably, the fibers selected are both compression resistant and wetand dry resilient (i.e., they tend to both resist compression and tospring back when compressed). Cross-linked cellulose fibers areespecially preferred for these criteria. (It is understood, however,that cross-linked cellulose fibers are sufficiently modified that theymay no longer be considered as either cellulosic, or as natural fibers,per se.)

The second group of fibers should also be of high compressive modulusand should maintain a relatively high modulus when wetted. The secondgroup of fibers should also preferably be wet and dry resilient.Suitable fibers include, but are not limited to synthetic fiberscomprised of any of those materials specified below as being suitablefor use as the fibers of the acquisition layer 46. (Fiber lengths,denier, etc. are, however, not necessarily the same. Some preferredfiber lengths, etc. are described below.)

The fibers in the second group of fibers are preferably longer than thefibers in the first group of fibers. Preferably, the fibers in thesecond group of fibers are greater than or equal to about 1/4 inch(about 0.6 cm.) long, and are more preferably greater than or equal toabout 1/2 inch (about 1.3 cm.) long. The denier of the fibers in thesecond group of fibers are preferably greater than the denier of thefibers in the first group of fibers. The fibers in the second group offibers preferably have a denier per filament of between about 6 andabout 40. More preferably, the denier is between about 15 and about 30,and most preferably between about 15 and about 25.

The fibers in the second group of fibers may be hydrophilic,hydrophobic, or partially hydrophilic and partially hydrophobic. Thefibers in the second group of fibers preferably have at least somehydrophilic component (preferably a cellulosic component). The fibers inthe second group of fibers can be provided with a hydrophilic componentin a number of suitable ways. These include, but are not limited tocoating or treating the fibers to render them, or at least theirsurfaces, hydrophilic.

Suitable synthetic fibers are available from Eastman Kodak TextileFibers Division Kingsport, Tenn. as the KODEL 200 and 400 Series. Onesuitable type of synthetic fiber is the KODEL 410 fiber.

One particularly suitable type of synthetic fibers for use in the secondgroup of fibers are crimped polyester fibers. A suitable polyester fiberis the KODEL 431 fiber. These KODEL fibers are preferably crimped at acrimping frequency of between about 5 and 7, preferably about 6, morepreferably 6.3 crimps per linear inch (i.e., per 2.5 cm.). The fibersare preferably crimped at a crimping angle of between about 700 to about90°, preferably about 88°. Crimping provides the fibers with improvedresilience, among other desired properties. The fibers have a denier of15 per filament and a length of about 0.5 inch (about 1.3 cm.). They maybe coated with a hydrophilic or hydrophobic finish by any suitablemethod known in the art.

In an alternative embodiment, it is possible to replace the cellulosefibers in the first group of fibers with very short, low denier,synthetic fibers (with hydrophilic surfaces). The blended core 42 inthis situation would consist of short, low denier, hydrophilic firstgroup of synthetic fibers (such as polyester fibers coated with aproprietary permanently wettable finish known as CELWET) and long, highdenier second group of synthetic fibers. Polyester fibers coated withCELWET are available from the Hoechst Celanese Corporation of Charlotte,N.C.

Such a blended core may also contain particles of hydrogel-formingpolymer gelling agents to increase the absorptive capacity of the core.

In one preferred embodiment, the hydrogel-forming polymer gelling agentscomprise "high-speed" absorbent gelling materials. The term "high-speed"absorbent gelling materials, as used herein, means those absorbentgelling materials that are capable of absorbing exudates at such a ratethat they reach at least about 40%, preferably at least about 50%, andmost preferably at least about 90% of their capacity in less than orequal to about 10 seconds.

A suitable method for measuring the percent rate of capacity isdescribed in U.S. patent application Ser. Nos. 07/637,090 and 07/637,571filed respectively by Noel, et al. and Feist, et al. In alternativeembodiments, it is also possible for the high-speed absorbent gellingmaterials to be mixed with other types (or ordinary speed) absorbentgelling materials.

Preferably, in the embodiment described immediately above, thehigh-speed absorbent gelling materials are in fibrous form. Fibroussuperabsorbent materials (though not necessarily fibrous high-speedabsorbent gelling materials) are discussed more fully in U.S. Pat. No.4,855,179, issued Aug. 8, 1989, to Bourland, et al.

The term "fibrous absorbent gelling materials", as used herein, isintended to include absorbent gelling materials in the form of fibersthat are comprised entirely of absorbent gelling material andbi-component fibers that are comprised at least partially of othermaterials which have their surfaces coated with absorbent gellingmaterials. A suitable fibrous high speed absorbent gelling material isknown as FIBERSORB SA7000 formerly manufactured by Arco Chemical Companyof Newton Square, Pa. Other suitable fibrous high speed superabsorbentfibers are the polyacrylate-based fibers known as FSA fiber Type 101,102, 111, or 112 available from Courtlauds Fibers, Ltd.

The effective utilization of hydrogel-forming polymer gelling agents isbelieved to be improved in such a blended core. The use of higherconcentrations of hydrogel-forming polymer gelling agents may also bepossible.

The blended absorbent core 42 is preferably compressed to a density ofat least about 1.5 g/cubic inch (about 0.09 g/cm³). The blended core 42may be compressed to densities at least as high as about 4.0 g/cubicinch (about 0.25 g/cm³) to improve fluid wicking while still maintaininggood softness and flexibility. (The density values specified above donot include the weight of any particles of absorbent gelling material.)Densification may be applied to the entire absorbent core 42 or only toselected portions. Patterned densification allows tailoring of the fluidhandling properties to a specific need. For example, the density may bevery low in the fluid target area to maximize fluid acquisition speed,and density may be very high near the core edges to maximize fluidwicking.

In one particularly preferred embodiment, the improved absorbent core 42is an air-laid blend comprised of approximately 15% of 0.5 inch long, 15denier per filament crimped polyester fibers and approximately 85% ofcross-linked cellulose fibers compressed to a density of about 1 g/cubicinch (about 0.06 g/cm³).

The blended absorbent core 42 can be used as the entire core or it canbe used as one or more layers in a layered construction. The blendedabsorbent core 42 can be used with or without an acquisition layer.

FIGS. 21-23 show an example of a core 42 in which layers of corematerial are used to produce a "profiled" sanitary napkin 20. Theprofiled sanitary napkin 20 is thicker in the center of the sanitarynapkin and tapers so it becomes thinner toward the edges 22 and 24.FIGS. 22 and 23 show that such a profiled sanitary napkin 20 can be madeby stacking layers having relatively large length and width dimensionson top of those with smaller length and widths (or vice versa).

In a layered construction, one or more layers can consist of allcellulose or cellulose/hydrogel-forming polymer material blends. Thelayers could also have differing fiber and/or absorbent gelling materialcontent or composition. For example, a higher percentage of absorbentgelling material could be provided in the lower layers to provideadditional liquid storage capacity.

In other embodiments, elastic fibers may be included in the second groupof fibers. Suitable elastic fibers include melt blown fibers, such asthose included in the hydro-entangled melt blown fiber and cottoncomposite known as product #7102-102 available from Fiberweb, or fibersmade of a polyethylene/Kraton blend, such as the material used to makeExxon film EXX-7.

(ii) Other Types of Cores

Other core structures that provide extensible properties includeunbonded nonwoven structures of synthetic fibers or various wovenstructures.

For instance, nonwoven structures including fibrous superabsorbentmaterials such as Fibersorb can be combined with various syntheticfibers to produce absorbent cores. These nonwoven structures can be madeextensible by utilizing various patterns of bonding and fiber lay down.

The stretch properties of these nonwoven structures can be enhanced byany of the different methods described herein, Suitable methods forenhancing the extensibility of stretch include, but are not limited toring rolling, including elastic fibers within the core, and includingfibers that are crimped or curled that are capable of being extended(such as those shown in FIGS. 58 and 59) for extensibility.

One suitable structure comprises the aforementioned melt blown elasticfibers and cotton Fiberweb product #7102-102 with superabsorbentmaterial. The superabsorbent material could be in either particulate orfibrous form. In other alternative embodiments, the structure couldcontain modified cross-linked cellulose fibers. The cross-linkedcellulose fibers could be added to the unbonded elastic fibers andsuperabsorbent material. In other embodiments, the cross-linked fiberscould replace the elastic fibers (if the cross-linked fibers areintrinsicly extensible), or the superabsorbent material.

(3) Providing the Core with Elasticity

The absorbent core 42 may be made not only extensible, but elasticallyextensible in any of the embodiments described in this specification.

The absorbent core 42 may be made elastically extensible even though ithas no elastic properties of its own. The absorbent core 42 can be madeelastically extensible by attaching it to an elastic backsheet ortopsheet so that the absorbent core 42 will extend and retract with theelastic topsheet or backsheet.

The sanitary napkin (or other absorbent article) 20 could also includeany additional absorbent layers or other components such as aredescribed in the patents incorporated by reference. For example, theabsorbent article may comprise an acquisition layer or patch ofcross-linked cellulose fibers positioned between the topsheet 38 and theabsorbent core 42.

C. The Backsheet

(1) General Characteristics of Preferred Backsheet Materials

The backsheet 40 is impervious to liquids and, thus, prevents bodyfluids from soiling the clothing of the user. A suitable backsheet 40may be manufactured from a wide range of materials. Suitable materialsinclude embossed or nonembossed polyethylene films and laminated tissue.

Suitable polyethylene film are manufactured by Monsanto ChemicalCorporation and marketed in the trade as Film No. 8020, by ClopayCorporation of Cincinnati, Ohio under the designation P18-0401, and byTredegar Film Products of Terre Haute, Ind. under the designationXP-39385.

In one alternative embodiment of the sanitary napkin 20 (typically inwhich the topsheet 38 overlays only the main body portion 21 and doesnot extend out to form the top surface of the flaps, if any), thebacksheet 40 may be comprised of two layers. In such a case, thebacksheet 40 may comprise a first layer of lofted material disposed onthe core-facing side 40A of the backsheet. The purpose of the firstlayer is to provide a comfortable, non-irritating surface against thebody of the wearer.

The lofted layer may be comprised of any suitable material, such as anonwoven material. Preferably, the lofted layer comprises a hydrophobicnonwoven material.

The second layer may be disposed on the garment side 408 of thebacksheet 40, and may comprise a fluid impervious film. A low densitypolyethylene material about 0.01 to about 0.05 millimeters in thickness,preferably about 0.02 millimeters in thickness, has been found to workwell as this second layer. A polyethylene film, such as is sold by theEthyl Corporation, Visqueen Division, under model XP-39385 has beenfound particularly well suited for this second layer. The backsheet 40may also be made of a soft, cloth-like material which is hydrophobicrelative to the topsheet 38. A polyester or polyolefinic fiber backsheet40 has been found to work well. A particularly preferred soft,cloth-like backsheet 40 material is a laminate of a polyester nonwovenmaterial and a film such as described in U.S. Pat. No. 4,476,180 issuedto Wnuk on Oct. 9, 1984.

(2) Providing the Backsheet With Extensibility

There are many possible types of extensible backsheets. These include,but are not limited to the embodiments described below.

Generally, many of the techniques described above for providing thetopsheet with extensibility may also be used to create an extensiblebacksheet 40. Thus, the backsheet materials can be made extensible byperforming a mechanical operation, such as pleating, corrugating, orring rolling the backsheet material. The backsheet 40 may be madeextensible by forming it from a film made of a stretchable material suchas Exxon film EXX-7 described above.

Typically, however, the films and the like used in constructing thebacksheet 40 are unapertured, or if apertured, provided with open areas,or the like, are made liquid impervious by covering the open areas,closing the open areas, reducing the size of the open areas, orotherwise.

A particularly preferred extensible backsheet 40 is an extended adhesivefilm Formula #198-338 manufactured by the Findley Adhesives Company ofWauwatosa, Wis. The Findley adhesive film is a fluid impervious filmcapable of extending 200-300%. It is preferred because it is alsoelastically extensible.

This film can be used "as is" in the sanitary napkin 20. One side of theadhesive film can be adhered to the garment-facing side 42B of theabsorbent core 42. The other side will comprise the garment-facing side40B of the backsheet 40, and may be used as a panty fastening adhesive.

Alternatively, the side of the adhesive film that forms thegarment-facing side 40B may have its adhesive surface at least partiallycovered (or "blocked" to eliminate its adhesive characteristics). Theadhesive body-facing side 40A of the backsheet can also be at leastpartially blocked.

The exposed adhesive can be blocked in a number of suitable ways. Theseinclude, but are not limited to attaching a layer of nonadhesivematerial to cover the exposed adhesive, and brushing or sprinkling apowdered material such as talcum powder or corn starch on at least partof the exposed adhesive. The partial blocking of the exposed adhesive onthe garment-facing side 40B of the backsheet 40 can be used with theremaining exposed adhesive to create particular panty fastening adhesivepatterns.

In still other embodiments, an adhesive film can be created with oneside that has adhesive tack, and one side without tack. One suitableadhesive film having these characteristics is a composite structurecomprising a nonwoven elastomeric film with a low modulus pressuresensitive adhesive, such as adhesive film Formula #198-338 which isavailable with a blocking film such as film Formula H2301 from theFindley Adhesives Company. Such materials are further described (andused for other purposes) in U.S. Pat. No. 5,032,120 issued to Freeland,et al. on Jul. 16, 1991, and U.S. Pat. No. 5,037,416 issued to Allen, etal. on Aug. 6, 1991.

In other preferred embodiments, the backsheet 40 can comprise anextensible laminate structure. Such a laminate can be comprised of twoor more layers. The laminate can be comprised of layers each of whichare capable of different extensibility. For instance, a backsheet 40could comprise a laminate formed of a layer of Findley adhesive filmthat is covered on one or both sides by an extensible nonwoven web or byan extensible film.

D. Combinations of Topsheet, Backsheet, and Core Materials

The sanitary napkin 20 of the present invention can be comprised of manydifferent combinations of the topsheet, backsheet, and core materialsdescribed herein.

As noted above, the sanitary napkin 20 may be comprised of allextensible components. The sanitary napkin 20 shown in FIGS. 1-3 could,for instance, comprise a topsheet, backsheet, and absorbent coreselected from any of those materials described above. The differenttypes of topsheet, backsheet, and absorbent core materials could beassembled in any of many possible combinations.

Alternatively, as noted above, the sanitary napkin 20 may be comprisedof some extensible components and some inextensible components. Thesanitary napkin could, for instance, be comprised of at least one of theextensible components described herein combined with any conventionalinextensible materials, or with at least some of the basic materialsdescribed above prior to providing these materials with extensibility toform many different structures. This can be done to achieve somedesirable performance characteristic, or to reduce the overall cost ofthe sanitary napkin 20.

FIGS. 23A-23C show some non-limiting examples of sanitary napkins formedwith some extensible and some inextensible components. Many otherexamples exist, as well, and are within the scope of the presentinvention.

FIGS. 23A and 23B show a sanitary napkin 20 having an extensibletopsheet 38 and backsheet 40 and an inextensible absorbent core 42. Theabsorbent core 42 is suspended relative to the topsheet 38 and backsheet40 by extensible strips or bands of material 101. The extensible strips101 are secured to the topsheet 3B and the backsheet 40.

The absorbent core 42 in such an embodiment, thus, forms a sling-likestructure positioned between the topsheet 38 and backsheet 40, and thetopsheet 38 and backsheet 40 form an extensible bag-like structurearound the absorbent core 42.

The sanitary napkin 20 shown in FIGS. 23A and 23B (especially thebacksheet 40 of the same) can, thus, extend with the wearer's pantiesfor fit and comfort. The inextensibility of the core 42 is advantageousin that it allows the capillary characteristics of the absorbent core 42to be maintained even when the topsheet 38 and backsheet 40 areextended.

FIG. 23C shows a sanitary napkin 20 having an extensible backsheet 40that is combined with an inextensible topsheet 38 and an inextensibleabsorbent core 42. The sanitary napkin 20 shown in FIG. 23C provides asimilar advantage to the sanitary napkin shown in the preceding figure.The sanitary napkin 20 in FIG. 23C, however, also provides severaladditional advantages.

The inextensibility of the topsheet 38 also allows the topsheet 38 tomaintain its capillary characteristics (which often forms a compositeabsorbent system with the absorbent core 42) when the backsheet isextended.

The sanitary napkin 20 shown in FIG. 23C also allows the components thatare intended to be near the wearer's body (the topsheet 38 and core 42)to fit adjacent the wearer's body without stretching. The backsheet 40which needs to adjust to the stretching of the wearer's parities, can doso.

The sanitary napkin 20 shown in FIG. 23C also has a pair oflongitudinally oriented extensible strips 99 along the body-facing sideof the sanitary napkin. The strips 99 can comprise a nonwoven material,or some other suitable material. The strips 99 are preferably soft toprovide a more comfortable surface for the wearer. The strips 99 alsoconnect the topsheet 38 to the backsheet 40. The strips 99 may, thus,serve as "isolation elements" (described below) which permit thebacksheet 40 to extend and stretch more independently of the topsheet 38and absorbent core 42 than if such strips were not present.

Several other alternative sanitary napkin embodiments having someextensible components and some inextensible components are those whichhave stretch attachment means for fastening to the wearer's panties.These are described below in Section 4A(1).

In addition to combining various different topsheet, backsheet, and corematerials, some of the materials specified herein can be used to servemore than one function, or as more than one component in an absorbentarticle.

For instance, some of the foam materials described herein as beingsuitable for use as an absorbent core can serve the functions of atopsheet, an absorbent core, and a backsheet. This can be accomplishedby applying an impervious coating to the garment-facing side of the foammaterial, or otherwise treating the garment-facing side of the foammaterial to render it liquid impervious. In another embodiment, thetopsheet 38 may be eliminated, and the underlying layer can serve thefunction that the topsheet 38 generally serves.

In addition, some of the materials described herein as being suitablefor use as one component, such as a topsheet (or as a backsheet orcore), can be used as one or more of the other components. (That is,provided that material has, or is modified to have, the desiredcharacteristics for the component.)

Further, the manners described herein of making one of the components(such as the topsheet, backsheet, or core) extensible can generally beused to make any of the other components extensible.

E. Assembly of the Topsheet, Backsheet, and Absorbent Core

The components of the sanitary napkin described above (the topsheet,backsheet, and absorbent core) can be secured together in any suitablemanner that allows the sanitary napkin 20 to extend.

In the preferred embodiment shown in FIG. 1, the components of thesanitary napkin 20 are sized so that the edges of the topsheet 38 andbacksheet 40 extend outward beyond the edges of the absorbent core 42.The backsheet 40 comprises a stretchable adhesive film. The core 42 isplaced on top of the backsheet 40. The topsheet 38 is then placed on topof the core 42. The portions of the edges of the topsheet 38 that extendoutward beyond those of the core 38 are secured to those of thebacksheet 40.

As shown in FIG. 1, the topsheet 38 is also preferably secured tobacksheet 40 along a first seam, such as seam 90. Seam 90 is preferablyliquid impervious. The seam 90 can be formed by any means commonly usedin the art for this purpose such as by gluing, crimping, orheat-sealing. The seam 90 is illustrated on the winged product shown inFIG. 5 as extending completely around the periphery of the main bodyportion 21.

It has been found that such a construction adequately secures thecomponents of the sanitary napkin without securing the faces of theadjacent components to each other. Although, as noted above, it is oftenpreferred to secure some of the components It their faces, as well.

The above is a preferred embodiment for ease of construction. (Othermeans of uniting the various components can be used.)

For instance, the present invention also includes so-called "tube"products. In these products, a liquid pervious cover material (such astopsheet material) can be wrapped completely around the absorbent coreand the backsheet, and then the components can be secured together. Inalternative arrangements, the topsheet could be wrapped around the core,and the wrapped core could be placed on and secured to the backsheet.

F. Fasteners for Attaching the Sanitary Napkin to the Wearer's Panties

(1) General Characteristics of Preferred Fasteners

The garment side 40B of the backsheet 40 may include fasteners (or"means for attaching the sanitary napkin to the undergarment of thewearer" or "attaching means")

FIG. 3 generally shows the central pad fastener, such as central padadhesive 44 which is adapted to secure the sanitary napkin 20 to thecrotch region of an undergarment. The central pad fastener 44 securesthe main body portion 21 in the crotch portion of a panty.

FIG. 5 shows the flap fastener, such as flap adhesive 45. The flapadhesives 4S are used to assist in maintaining the flaps 52 in positionafter they are wrapped around the edges of the crotch portion of thepanty as described below. The flap adhesive 45 is located on the outersurface of flap 52, adjacent the distal edges 53 of the flaps 52 (i.e.,the end of the flaps 52 farthest away from the longitudinal centerline Lof the sanitary napkin 20). The flaps 52 can be maintained in positionby attaching the flaps 52 to the undergarment, or to the opposing flap.

The adhesive fasteners are respectively covered by removable coverstrips or release liners, such as central pad release liner and flaprelease liner, both designated 50. The adhesives should be covered withrelease liners 50 to keep the adhesives from sticking to extraneoussurfaces prior to use. Suitable release liners are described in U.S.Pat. No. 4,917,697.

The fasteners have been initially described in terms of adhesives forsimplicity of description. The types of fasteners are not limited toadhesives, however. Preferred fasteners include but are not limited toadhesive fastening means, such as pressure sensitive adhesives,mechanical fasteners and combinations of adhesives and mechanicalfasteners. The preferred types of fasteners and configurations thereofare described in greater detail below.

(a) Adhesive Fasteners.

Pressure sensitive adhesives, if used, may be applied to the garmentside 40B of the backsheet 40 in many different patterns orconfigurations.

The adhesive configurations may be used for a variety of purposes inthin, flexible sanitary napkins. International Patent ApplicationPublication No. WO 92/04000 entitled "Shape and Adhesive Fastening Meansfor an Absorbent Article" published in the names of Papa, et al. on Mar.19, 1992, incorporated by reference herein, discloses configurations canbe used to: (1) allow the sanitary napkin to conform to the body of thewearer; (2) reduce the tendency of the longitudinal edges of thesanitary napkin to roll over and bunch, and the tendency of the endedges to flip over and bring the panty adhesives in contact with thewearer's body and pubic hair.

The Papa, et al. patent application teaches that the overall width ofthe adhesive fasteners should be as close as possible to the width ofthe crotch region of the wearer's panties to reduce the tendency of thepanty elastics to apply forces that flip back the longitudinal edges ofthe napkin. The Papa, et al. patent application also teaches that in atleast some embodiments, there should be an area along the longitudinalcenterline L of the sanitary napkin 20 where the backsheet 40 isunattached to the wearer's panties to allow this central portion of thebacksheet 40 to separate from the panties and the sanitary napkin todeform into a W-shape in transverse cross-section similar to that shownin FIG. 69.

The Papa, et al. patent application teaches that the adhesive should beclose to the end edges 24 of the sanitary napkin to reduce end flipping,but not too close. The adhesive should not be too close to the end edges24 because the slightest amount of end flipping will cause the adhesiveto come in contact with the wearer's body. The adhesive shouldpreferably be no more than about 6 mm. from the end edges 24, and mostpreferably no more than about 6 mm. plus or minus about 3 mm.

The adhesive configurations in the present invention can be used toaccomplish these same purposes, and to provide sanitary napkins thatadjust to the dynamic changes of the wearer's body and panties when thesanitary napkin is worn.

The adhesive configurations that can be used depends on whetherextensible or inextensible adhesives are used. The portion of thesanitary napkin on which extensible adhesives are located will beextensible. Sanitary napkins containing inextensible adhesives willtypically only be capable of extension between the inextensible adhesivepatches. Therefore, if inextensible adhesives are used, they arepreferably applied in intermittent patterns to permit the sanitarynapkin to extend between adhesive patches.

The adhesive can be applied in many configurations, including, but notlimited to the following: (1) a single zone or patch of adhesive; (2)two parallel longitudinally-oriented strips on opposite sides of thelongitudinal centerline; (3) two inwardly-arcuate strips of adhesive;and (4) multiple patches of adhesive. The adhesive can be applied incontinuous or intermittent patterns in the above configurations (andother configurations) if the adhesive is extensible. As indicated above,if the adhesive is not extensible, it is preferably applied inintermittent patterns, including but not limited to intermittent dots,intermittent strips, and the like.

FIG. 3 shows one preferred adhesive configuration for use on thesanitary napkin of the present invention.

The adhesive configuration shown comprises six 3/4"×3/4" (about 2 cm.×2cm.) square pieces and two 3/4"×2.5" (about 2 cm.×6.4 cm.)longitudinally-oriented rectangular pieces. One rectangular piece ispositioned on each side of the longitudinal centerline L. The squarepieces are placed in the end regions 28 and 30 of the sanitary napkin.The square pieces are placed so that in each end region, one piece is ineach corner 27, and one is disposed along the longitudinal centerline.

The adhesive patches 44 can each be covered with a separate cover strip50. However, the patches are preferably covered with a single releasesheet. This allows for ease of manufacture and benefits the consumer whodoes not have to dispose of several small individual cover strips 50.

If the adhesives are extensible, they preferably extend approximatelythe same amounts as the sanitary napkin as set forth in Table 1.

Suitable extensible adhesives include extensible adhesives, per se, andextensible adhesive/backsheet combinations. Any extensible adhesivesknown in the art can be used. Suitable extensible adhesive/backsheetcombinations include, but are not limited to non-extensible adhesiveused on an extensible backsheet material known as 3 Sigma 2474 availablefrom Anchor Continental, inc., 3 Sigma Division, of Covington, Ohio;elastically stretchable adhesive films such as Findley adhesive 198-338,or an elastically stretchable adhesive film known as 3M XPO-0-014available from the Minnesota Mining and Manufacturing Company of St.Paul, Minn.; or spray adhesives such as 3M adhesive 1442 on a lowmodulus elastic film.

Suitable inextensible adhesives may be those adhesives specified as 0.6mil pass available from Century Adhesive as product number A305-4, orfrom Anchor Continental, Inc., 3 Sigma Division, of Covington, Ohio.Suitable inextenstble adhesive fasteners are described in greater detailin U.S. Pat. No. 4,917,697.

(b) Mechanical Fasteners, Frictional Fasteners, and the Like.

The fasteners used with all of the various embodiments of the presentinvention described herein are not limited to adhesive attachment means.Any type of fastener used in the art can be used for such purpose.

For example, the sanitary napkin 20 could be secured to the wearer'sundergarment by conventional VELCRO hook material, or by the fastenersdescribed in U.S. Pat. No. 4,946,527 issued to Battrel on Aug. 7, 1990,U.S. Pat. Nos. 5,058,247 and 5,116,563 issued to Thomas, et al. on Oct.22, 1991 and May 26, 1992, respectively, and EPO patent applicationpublication No. 0 381 087 published Aug. 8, 1990, or high coefficient offriction foams and other high coefficient of friction materials such asthose described in U.S. Pat. No. 4,166,464 issued to Korpman, U.S. Pat.No. 4,834,739 issued to Linker, III, et al., and U.S. Pat. No. 5,011,480issued to Gossens, et al.

The stretching forces exerted on the garment surface 208 of the sanitarynapkin 20 by the wearer's parities, moving in response to the wearer'sbody motions accounts for many of the problems that lead to adhesivefasteners becoming unattached from the wearer's panties. The use ofmechanical fasteners on stretchable absorbent articles is believed to beparticularly beneficial, due to their tendency to reduce the effect ofthese shearing forces. Mechanical fasteners that engage the fabric ofthe wearer's panties will move with the panties, reducing the problemscaused by these shearing forces.

G. Optional Components of the Sanitary Napkin

The sanitary napkin 20 of the present invention may be provided withoptional additional components. (If desired, these additional componentsmay be provided with extensibility in any of the manners describedherein.)

The sanitary napkin 20 of the present invention can be provided with oneor more additional pervious or absorbent layers. The additional perviousor absorbent layers may be positioned between the absorbent core 42 andeither the topsheet 38, the backsheet 40, or both. As shown in FIG. 6,an absorbent layer, such as wicking layer 46, is positioned between thetopsheet 38 and the absorbent core 42. This wicking layer 46 may bereferred to as a secondary topsheet, or "wipe acquisition sheet", or"acquisition layer".

In the embodiment shown in FIG. 6, the acquisition layer 46 is a foldedsheet of nonwoven material. It should be understood, however, that theacquisition layer 46 need not be a folded sheet. The terms "layer" or"web", as used herein to describe the acquisition layer, include, butare not limited to single unfolded sheets, folded sheets, strips ofmaterial, loose or bonded fibers, multiple layers or laminates ofmaterial, or other combinations of such materials. The terms layers andwebs are thus, not limited to single unfolded layers or sheets ofmaterial.

In FIG. 6, the acquisition layer 46 is a "double" z-folded sheet. Thesheet 46, is more specifically folded so that when the sanitary napkinis cut along the transverse centerline T, the left half of the foldedsheet appears as a reverse "z" in cross section and the right halfappears as a "z". The sheet 46 is preferably folded so that it has anupper portion 49 that appears as a rectangular strip in plan view. Theupper portion 49 of the acquisition layer 46 is preferably about 227 mmlong, and between about 25 and about 38 mm wide. The upper portion 49preferably has a caliper of from about 0.5 mm up to about 4 mm (thehigher end of this range creates thicker products). Such a foldedarrangement is described in greater detail in PCT Patent ApplicationPublication No. WO 92/07535 published in the name of Visscher, et al. onMay 14, 1992.

FIG. 7 is a simplified cross-sectional view similar to that of FIG. 6,showing an alternative arrangement of the components of the sanitarynapkin 20. In FIG. 7, rather than being a separate layer that is locatedon top of the core 42, the acquisition layer 46 is an integral layer (orcomponent) that comprises the top layer of a laminated absorbent core 42structure.

The acquisition layer 46 serves to improve wicking of exudates over andinto the absorbent core 42. There are several reasons why the improvedwicking of exudates is important. The improved wicking provides a moreeven distribution of the exudates throughout the absorbent core.

The improved wicking also allows the sanitary napkin 20 of the presentinvention to be made relatively thin. The acquisition layer 46 iscapable of dispersing exudates over a large surface area of theabsorbent core 42. The acquisition layer 46 thus allows the sanitarynapkin 20 to absorb relatively large amounts of exudates. Bulky priorart sanitary napkins relied on a high degree of vertical absorption atthe point where exudates are initially deposited. Because the absorbentcores of these prior napkins were fairly thick, they could absorb alarge volume of exudates while utilizing only a small degree of thesurface area or lateral absorption capacity. The thin versions of thesanitary napkins 20 of the present invention may absorb relatively largeamounts of exudates because the wicking disperses the exudates over alarge surface area of the absorbent core 42 where the exudates canbetter and faster be vertically absorbed into the absorbent core 42.

The acquisition layer 46 may also be used to direct exudates toward theends of the core 42D. Liquid exudates that are deposited on the core 42will tend to be distributed radially outward from the place where theyare deposited. Since the core 42 of the sanitary napkin 20 is relativelynarrow in comparison to its length, liquid exudates will reach thelongitudinal edges 42C of the core 42C much sooner than they will reachthe ends 42D of the absorbent core. The acquisition layer 46 can be usedto longitudinally wick and direct exudates toward the ends 42D of thecore 42. This more effectively utilizes the capacity of the core, andreduces the possibility of leakage caused by exudates prematurelyreaching the longitudinal edges 42C of the core.

The characteristics of the acquisition layer 46 are as follows. Theacquisition layer 46 should be liquid permeable. The acquisition layer46 is also preferably compliant, soft feeling, and non-irritating to theuser's skin. It can be made from any materials that are capable ofdispersing exudates in the preferred manner described above. Thematerials may also be capable of having the topsheet 38 fused to them.The acquisition layer 46 is preferably provided with stretch properties.The acquisition layer 46 has a body-facing face (or side) 46A, and agarment-facing face 46B.

The acquisition layer 46 should be hydrophilic. The fibers or yarns 55comprising the acquisition layer 46 may be inherently hydrophilic.Alternatively, they may be treated to render them hydrophilic. Suitablemethods for rendering fibers hydrophilic include treating them with asurfactant. The fibers can be treated by spraying the materialcomprising the acquisition layer with a surfactant or immersing thematerial into the surfactant. A more detailed discussion of such atreatment and hydrophilicity is contained in U.S. Pat. Nos. 4,988,344and 4,988,345 issued to Reising, et al. and to Reising, respectively.The hydrophilicity of these fibers allows the acquisition layer 46 todraw liquid exudates through the topsheet 38 from below.

The acquisition layer 46 may be comprised of many of the same materialsas the absorbent core. The acquisition layer 46 may be comprised ofwoven or nonwoven materials. These materials may be synthetic, orpartially synthetic and partially natural materials. Suitable syntheticfibers include polyester, polypropylene, polyethylene, nylon, viscousrayon fibers, or cellulose acetate, with polyester fibers beingpreferred. Suitable natural fibers include cotton, cellulose, or othernatural fibers. The acquisition layer 46 may also be at least partiallycomprised of cross-linked cellulose fibers, or as in the case of thepreferred embodiments described in the Examples set forth below,capillary channel fibers.

The acquisition layer 46 can also be comprised of combinations of theabove materials, such as blends of fibers similar to those describedabove for use in the blended absorbent core, or any equivalent materialor combinations of materials.

The fibers or yarns 55 comprising the acquisition layer 46 may be of anylength, from staple length to continuous filaments. The length of thefibers 55 is preferably between about 1 inch and about 3 inches (betweenabout 2.5 cm. and about 7.5 cm.), and most preferably is about 1.5inches (about 3.8 cm.). The fibers 55 preferably have a denier perfilament of between about 1 and about 3, most preferably about 1.5.

The fibers 55 of the acquisition layer 46 are preferably orientedprimarily in a single direction. Typically, the acquisition layer 46 canbe manufactured with its fibers oriented in the machine direction (MD).The acquisition layer 46 can be placed in the product with most of thefibers 55 oriented in either the longitudinal direction or thetransverse direction. (That is, the fibers 55 are generally parallel toeither the longitudinal or transverse centerlines L of the sanitarynapkin 20).

The phrases "generally parallel" to one of the centerlines, as usedherein, are intended to include fibers that angle away from therespective centerline. The fibers are considered to be generallyparallel to the longitudinal centerline as long as they are orientedmore in the longitudinal direction than the transverse direction.

The orientation of the fibers 55 in the acquisition layer 46 in thelongitudinal direction may be used to cause liquid exudates deposited onthe acquisition layer 46 to preferentially wick and be distributedtoward the ends 42D of the absorbent core 42. If the fibers 55 in theacquisition layer are generally parallel to the longitudinal centerlineL, however, some operation, such as ring rolling, generally must beperformed on the acquisition layer 46 for the acquisition layer to beextensible in the longitudinal direction.

The acquisition layer 46 may be any suitable size. The acquisition layer46 need not extend the full width of the absorbent core 42. Theacquisition layer 46 could, for instance, be in the form of a strippositioned similarly to (and of a size similar to) the upper portion 49of the z-folded sheet shown in FIGS. 5 and 6.

The acquisition layer 46, if nonwoven, can be made by a number ofdifferent processes. These include, but are not limited to the followingin order of preference from least to most preferred: meltblown,spunbonded, carded, the latter including, in order of preference,thermally-bonded, air-through bonded, powder bonded, latex bonded,solvent bonded, or most preferably, spunlaced. The latter processes aremore preferred because it is easier to orient the fibers in a singledirection in such processes.

Suitable commercially available products for use as the acquisitionlayer 46 include a 70%/30% rayon/polyester fabric known as SONTARA. TheSONTARA fabric is described in greater detail in U.S. Pat. Nos.4,950,264 and 5,009,653 issued to Osborn.

In a particularly preferred embodiment, the acquisition layer 46comprises a spunlace nonwoven web comprised of permanently wettablefibers. Preferably, the acquisition layer 46 is a 30 g/yard² (35 g/m²)polyethylene theraphtalate (or PET) spunlace nonwoven web. Spunlacedfabrics of this type are manufactured by the Veratec Company of Walpole,Mass. The spunlace nonwoven web is formed in such a way that most of thefibers are oriented in a single direction.

The fibers of this particularly preferred acquisition layer 46 materialare made of a PET resin and are coated with the permanently wettableCELWET finish. The term "permanently wettable", as used herein, refersto fibers that will sink in less than or equal to about 7 seconds whentested according to the ASTM D 1117-74 Basket Sink Method.

The CELWET finish is particularly preferred for use in sanitary napkinshaving a topsheet 38 comprising an apertured film or scrim withhydro-entangled nonwoven fibers such as that described in U.S. patentapplication Ser. No. 07/810,744 filed in the name of Cree, et al. onDec. 17, 1991, because fibers coated with it remain extremelyhydrophilic after hydro-entangling processes, and therefore, wick bloodvery well.

In another particularly preferred embodiment, the acquisition layer 46comprises a spunbonded polypropylene nonwoven CELESTRA fabric known asP-9 manufactured by the Fiberweb Group.

If desired, the sanitary napkin 20 may be additionally provided withflaps 52 that extend outwardly from each longitudinal edge 22 of thesanitary napkin 20. The flaps 52 may be in any suitable configuration.Suitable flaps 52 may, for example, be made in accordance with theteachings of U.S. Pat. No. 4,589,876, issued May 20, 1986 to Van Tilburgand U.S. Pat. No. 4,687,478, issued Aug. 18, 1987 to Van Tilburg, U.S.patent application Ser. No. 07/769,891 entitled "Absorbent ArticleHaving Flaps and Zones of Differential Extensibility" filed Oct. 1, 1991in the name of Lavash, et al., U.S. patent application Ser. No.07/832,246 entitled "Absorbent Article Having Inwardly-Folded PleatedFlaps filed Feb. 7, 1992 in the name of Niihara, et al., Ser. No.07/707,233 entitled "Sanitary Napkin Having Laterally Extensible Heartsfor Attachment to the Undergarment of the Wearer", filed May 21, 1991 inthe name of Osborn, et al., the disclosures of which patents areincorporated herein by reference.

The following Examples further illustrate the practice of the presentinvention, particularly those sanitary napkins which utilize capillarychannel fibers in the construction of the same. The following Examples,however, are not intended to limit the scope of the absorbent articlesencompassed therein.

EXAMPLE I THICK PAD

A sanitary napkin article is hand-made using the following components.Reference is made to FIG. 18 for the assembly of the product.

The topsheet 38 is made in accordance with U.S. Pat. No. 4,463,045 andring rolled to provide it with longitudinal extensibility.

The absorbent core 42 is a superabsorbent material laminate as describedabove which is slatted or partially slitted for longitudinalextensibility. FIG. 18 shows an absorbent core 42 that is slit at theend regions 28 and 30, but not at the central region 32. The backsheet40 is an extended adhesive film known as Formula #198-388 manufacturedby the Findley Adhesives Company of Wauwatosa, Wis.

The sanitary napkin 20 shown in FIG. 18 also preferably comprises alayer of capillary channel fibers 150. The thick pad comprises a swatch152 of capillary channel fibers. In the thin sanitary napkin describedin Examples II and III below, the swatch 152 of fibers is eliminated,and the layer of capillary channel fibers may be gathered at the centerinto a tuft 154. The sanitary napkin 20 further comprises a crepedBOUNTY (TM) paper towel layer 156 and polyethylene end guards 158.

FIG. 18 shows one preferred adhesive configuration for use on thisextensible sanitary napkin embodiment. The adhesive configuration showncomprises six 3/4"×3/4" (about 2 cm.×2 cm.) square pieces of adhesive 44and two 3/4"×2.5" (about 2 cm.×6.4 cm.) longitudinally-orientedrectangular pieces 44. One rectangular piece is positioned on each sideof the longitudinal centerline L. The square pieces are placed in theend regions 28 and 30 of the sanitary napkin 20. The square pieces areplaced so that in each end region, one piece is in each corner 27, andone is disposed along the longitudinal centerline L.

The adhesive patches 44 can be extensible, inextensible, or some patchescan be extensible and some inextensible.

The adhesive patches 44 can each be covered with a separate releaseliner or cover strip SO. However, the patches are preferably coveredwith a single release sheet for ease of manufacture and so that theconsumer does not have to dispose of several small individual coverstrips 50. Any commercially available release liner can be used. In onepreferred embodiment, the release liner could be replaced by a wrapperthat provides both an individually packaged sanitary napkin and acontainer for disposing the sanitary napkin after use, such as isdescribed in U.S. Pat. No. 4,556,146 issued to Swanson, et al. on Dec.3, 1985.

The capillary channel fibers are preferably substantially curled.Suitable capillary channel fibers are those designated SW194 availablefrom the Eastman Chemical Company. The SW194 fibers comprise a cardedstaple slaver which has been stuffer box crimped to 7.8 crimps per inchand have an H-shaped cross-section with a channel width of 37 microns, achannel depth of 48 microns, and a denier of approximately 22 dpf. Thecapillary channel fibers are preferably 6 in. long; 0.75 g. fibers areused.

In the making procedure, the ring rolled topsheet is cut to the desiredsize, a template (2"×7" opening) is placed on the back side of thetopsheet and sprayed with the Findley 4031 adhesive. The adhesive isapplied in a spiral pattern (see FIG. 18A).

The layer of capillary channel fibers SW194 is hand-pressed in thecenter of the glue sprayed area with the fibers running parallel to thelong axis of the topsheet. The capillary channel fibers are preferablypressed into the center of the glued area so that they at leastpartially cover at least some apertures of the topsheet. The capillarychannel fibers may also at least partially protrude into the aperturesof the topsheet.

The capillary channel fibers SW173 are hand pressed as a swatch (withfibers parallel to the long axis of the article) in the center of thelayer capillary channel SW194 fibers. This provides a Pre-Assembly ofthe topsheet and capillary channel fibers.

For convenience, the remainder of the procedure is carried out using mconcave forming die. The Findley adhesive backsheet (polyethylenebacksheet with adhesive coating and release paper) is placed in theform. The slitted superabsorbent (or absorbent gelling material, or"AGM") laminated core is placed over the backsheet, and the crepedtissue (BOUNTY) is placed over the AGM core. The Pre-Assembly, preparedabove, is placed over the creped tissue. With the Pre-Assembly over thecreped tissue, the article's components are pulled snugly over the edgesof the form, but not so tightly that the components begin to pull awayfrom the form. Firm pressure is applied to adhere the edges with theadhesive on the backsheet.

The article is removed from the form and the ends are pressed in placeusing a roller. The release paper is peeled from the back of thebacksheet. The end guard polyethylene strips are added and the strips ofpanty fastening adhesive are placed on the article. The outer surface ofthe topsheet is sprayed with 0.01 g of PEGOSPERSE surfactant availablefrom Lonza, Inc., Williamsport, Pa.

The specifications of the finished product are as follows.

    ______________________________________                                                               Specifications                                         ______________________________________                                        Parameter                                                                     Pad weight (g)           9.82 ± 0.12                                       Core weight (g) laminate only                                                                          2.57 ± 0.04                                       Pad length (mm)          226 ± 1                                           Core length (mm)         197 ± 1                                           Pad width at center (mm) 81 ± 2                                            Core width at center (mm)                                                                              70 ± 0                                            Pad caliper (inches at 0.13 psi)                                                                       0.611 ± 0.02                                      Core caliper (inches at 0.13 psi)                                                                      0.058 ± 0.003                                     Seal length (m)          8 ± 1                                             Components                                                                    Polyethylene ring rolled formed-film topsheet                                                          ca. 9" × 5"                                    (according to U.S. Pat. No. 4,463,045)                                        Capillary channel fibers SW194 (Eastman)                                                               1.5 g                                                Capillary channel fibers SW173 (Eastman)                                                               0.5 g.                                               Findley extensible adhesive film backsheet                                                             9" × 5"                                        (Formula #198-338)                                                            Creped BOUNTY paper towel                                                                              Shaped*                                              Panty fastening adhesive Six 3/4" × 3/4"                                                         pieces; two                                                                   3/4" × 2.5"                                                             pieces                                               Release paper            As needed                                            Surfactant (PEGOSPERSE)  0.01 g                                               White poly for ends      4" × 0.75"                                     Absorbent gelling material (AGM) slit core                                                             70 mm × 193 mm                                 non-slit central area; total core wt.                                                                  with 23/4"                                           2.6 g; contains 0.7 g polyacrylate AGM                                                                 non-slit                                                                      center area                                          Findley Adhesive-4031    0.05 g                                               ______________________________________                                         *See FIG. 18(38) for shape. The shape is designed to provide anatomical       fit.                                                                     

EXAMPLE II THIN PAD

Reference is made to FIG. 18. The assembly of the thin pad isequivalent, except that CCF SW173 fibers are used in place of the layerof CCF SW194 fibers (150), and no swatch (152) of fibers is used.

Assembly of the product is as follows. Cut capillary channel fibers (CCFSW173) to 7 in. length; 0.75 g fibers used. Cut the ring-rolled topsheetto size. Place the template on the bottom side of the topsheet and applyFindley 4031 adhesive (spiral pattern). Hand-press CCF SW173 fibers inthe center of the glued area with the fibers running substantiallyparallel to the long axis of the topsheet. Lay the Findley backsheet onflat surface. Place the slatted AGM laminate core on the Findleybacksheet. Center the creped BOUNTY tissue (shaped similarly to thetopsheet) over the laminate core. Center the topsheet/capillary channelfiber Pre-Assembly over the creped tissue. Secure the Pre-Assembly andsmooth at edges. Roll the edges to seal. Peel the release paper from theback of the pad. Tear and remove in 2 or 3 pieces, then place the polyon the ends of the article. Place the panty fastening device (PFA) onthe pad. Spray the topsheet with 0.01 g. PEGOSPERSE surfactant.

The specifications of the finished product are as follows.

    ______________________________________                                                               Specifications                                         ______________________________________                                        Parameter                                                                     Pad weight (g)           8.50 ± 0.18                                       Core weight (g) laminate 2.54 ± 0.09                                       Pad length (mm)          232 ± 4                                           Core length (mm) laminate                                                                              201 ± 1                                           Pad width at center (mm) 85 ± 1                                            Core width at center (mm)                                                                              65 ± 1                                            Pad caliper (in. at 0.13 psi)                                                                          0.211 ± 0.005                                     Core caliper (in. at 0.13 psi)                                                                         0.074 ± 0.003                                     Components                                                                    Polyethylene formed-film topsheet (ring rolled;                                                        9" × 5"                                        per U.S. Pat. No. 4,463,045)                                                  Capillary channel fibers SW173 (Eastman)                                                               0.75 g;                                                                       7" length                                            Findley extensible adhesive film backsheet                                                             -9" × 5"                                       (Formula #198-338)                                                            Creped BOUNTY paper towel                                                                              Shaped*                                              PFA (panty fastening adhesive)                                                                         Six 3/4" × 3/4"                                                         pieces and two                                                                3/4" × 2.5"                                                             pieces                                               Release paper            As needed                                            PEGOSPERSE               0.01 g                                               White poly for ends      4" × 3/4"                                      AGM slit core non-slit center; total                                                                   65 mm × 193 mm                                 core weight 2.5 g; contains 0.7 g AGM                                                                  with 23/4"                                                                    non-slit center                                      Findley 4031 (adhesive)  0.05 g                                               ______________________________________                                         *As in Example I.                                                        

As noted above, in one preferred mode of this stretchable sanitarynapkin 20, the central portion of the layer 150 of capillary channelfibers can be gathered into a small "loop" or "tuft" 154. This loop ortuft 154 thus extends upward from the layer of capillary channel fibersto firmly contact the topsheet 38. Moreover, the loop or tuft 154 ispositioned centrally in the overall article, such that it can providerapid acquisition and transport of fluid into the remaining portion ofthe layer of capillary channel fibers, and thence into the fluid storagelayer of the article.

Advantageously, such "loop" or "tuft" not only concentrates capillarychannel fibers at the point where fluid impinges onto the article, butalso orients the capillary channel fibers which comprise the loop ortuft substantially in the upward z-direction, thus enhancing fluidmovement in the downward z-direction of the article. The followingExample illustrates an absorbent article having a substantially central,z-directional tuft of capillary channel fibers.

EXAMPLE III PAD WITH CENTRAL TUFT OF FIBERS

A layer of capillary channel fibers of the type disclosed herein (with a6-inch length) is gathered in its center to provide a slightly raisedoval "tuft" having the approximate dimensions: 2-3 inches x-direction(or longitudinal dimension); 1.5 inches y-direction (or lateraldimension) at widest point; and 5 mm-10 mm z-direction.

The tufted bundle of fibers can be held in its tufted configuration byany convenient means. Typically, the tuft is passed through a confiningslit in a sheet of paper or hydrophilic polymer. Using the proceduresdisclosed herein, the tufted bundle of fibers is assembled into anabsorbent article with the tuft residing approximately at the center ofthe overlying topsheet, and with the tuft in close contact with thetopsheet, as explained hereinabove.

In use as a sanitary napkin, the article is positioned (e.g.,intralabially) to maximize fluid uptake by the tuft. In an alternatemode, the ends of the looped fibers in the tuft are cut to provide afleece-like, z-directional bundle of open-ended capillary channelfibers. In still another embodiment, the layer of capillary channelfibers comprising the base of the tuft is positioned wholly or partlywithin the wet-laid or dry-laid absorbent core of the article, ratherthan atop the core. In this latter embodiment, a commercially-availablelayered laminate core comprising two outer tissue layers with anintermediate layer of absorbent gelling material (AGM) can be used. Thecapillary channels at the base of the tuft can be slipped into theinternal, AGM-containing layer.

EXAMPLE IV ULTRA-THIN PAD

Reference is made to FIG. 18. The assembly of the ultra-thin pad isequivalent, except that no swatches of capillary channel fibers areused.

Assembly of the product is as follows. Cut the ring-rolled topsheet tosize. Place the template on the bottom side of the topsheet and applyFindley 4031 adhesive (spiral pattern). Lay the Findley backsheet onflat surface. Place the slatted AGM laminate core on the Findleybacksheet. Center the creped BOUNTY tissue (shaped similarly to thetopsheet) over the laminate core. Place the topsheet over the crepedtissue. Secure the components and smooth at edges. Roll the edges toseal. Peel the release paper from the back of the pad. Tear and removein 2 or 3 pieces, then place the poly on the ends of the article. Placethe panty fastening device (PFA) on the pad. Spray the topsheet with0.01 g. PEGOSPERSE surfactant.

The specifications of the finished product are as follows.

    ______________________________________                                                               Specifications                                         ______________________________________                                        Parameter                                                                     Pad weight (g)           8.50 ± 0.18                                       Core weight (g) laminate 2.54 ± 0.09                                       Pad length (mm)          232 ± 4                                           Core length (mm) laminate                                                                              201 ± 1                                           Pad width at center (mm) 85 ± 1                                            Core width at center (mm)                                                                              65 ± 1                                            Pad caliper (in. at 0.13 psi)                                                                          0.11 ± 0.01                                                                (2.9 mm)                                             Core caliper (in. at 0.13 psi)                                                                         0.074 ± 0.003                                     Components                                                                    Polyethylene formed-film topsheet (ring rolled;                                                        9" × 5"                                        per U.S. Pat. No. 4,463,045)                                                  Findley extensible adhesive film backsheet                                                             -9" × 5"                                       (Formula #198-338)                                                            Creped BOUNTY paper towel                                                                              Shaped*                                              PFA (panty fastening adhesive)                                                                         Six 3/4" × 3/4"                                                         pieces and two                                                                3/4" × 2.5"                                                             pieces                                               Release paper            As needed                                            PEGOSPERSE               0.01 g                                               White poly for ends      4" × 3/4"                                      AGM slit core non-slit center; total                                                                   65 mm × 193 mm                                 core weight 2.5 g; contains 0.7 g AGM                                                                  with 23/4"                                                                    non-slit center                                      Findley 4031 (adhesive)  0.05 g                                               ______________________________________                                         *As in Example I.                                                        

4. Alternative Embodiments

In alternative embodiments, components of regions of the sanitary napkinmay be structurally modified by folding, bending, corrugating, stackingof layers and affixing layers to each other. The modifications may bemade by including one or more of the structures described in theaforementioned European patent applications published in the name ofBuell, in the aforementioned U.S. patent application filed in the nameof Visscher, et al., and in U.S. patent application Ser. No. 07/874,872entitled "Generally Thin, Flexible Sanitary Napkin filed in the name ofOsborn on Apr. 28, 1992.

In still other alternative embodiments, the sanitary napkin could beprovided with additional components. For instance, the sanitary napkincould be provided with the wet-laid tissue and/or the liquid permeablewipe acquisition sheet described in greater detail in U.S. Pat. No.5,009,653 issued to Osborn.

In yet other alternative embodiments, the sanitary napkin could beprovided in a curved, shaped configuration such as that described in thefollowing patent applications filed on the same date as the presentapplication: U.S. patent application Ser. No. 07/915,285, entitled"Curved, Shaped Absorbent Article" filed in the name of Theresa L.Johnson, et al.; U.S. patent application Ser. No. 07/915,202, entitled"Absorbent Article Having Resilient Center" filed in the name of ThomasW. Osborn, et al.; U.S. patent application Ser. No. 07/915,201, entitled"Absorbent Article Fastener Pattern" filed in the name of Robb E. Olsen,et al.; and, U.S. patent application Ser. No. 07/915,134, entitled"Method of Making Curved, Shaped Absorbent Article" filed in the name ofLetha M. Hines, et al.

Thus, while the sanitary napkins of the present invention may typicallybe comprised of components that extend together to a sufficient degreewhen stretched such that the extended configuration of the sanitarynapkin is not curved, in other embodiments the extension of thecomponents could result in a curved product.

While several preferred sanitary napkin embodiments have been described,numerous other sanitary napkin embodiments are disclosed in theliterature. These could be provided with the stretch properties of thepresent invention. Some of such sanitary napkins are described in U.S.patent application Ser. No. 07/605,583 filed Oct. 29, 1990 in the nameof Visscher, et al., U.S. Pat. Nos. 5,009,653 and 4,950,264, issued toOsborn on Apr. 23, 1991 and Aug. 21, 1990, respectively, U.S. Pat. No.4,940,462, issued to Salerno on Jul. 10, 1990, U.S. Pat. No. 4,917,697issued to Osborn, III, et al. on Apr. 17, 1990, U.S. Pat. No. 4,911,701issued to Mavinkurve on Mar. 27, 1990, U.S. Pat. No. 4,900,320, issuedto McCoy on Feb. 13, 1990, U.S. Pat. No. 4,687,478 issued to Van Tilburgon Aug. 18, 1987, U.S. Pat. No. 4,608,047 issued to Mattingly on Aug.26, 1986, U.S. Pat. No. 4,589,876 issued to Van Tilburg on May 20, 1986,U.S. Pat. No. 4,285,343 issued to McNair on Aug. 25, 1981, U.S. Pat. No.3,397,697 issued to Rickard on Aug. 20, 1968, and U.S. Pat. No.2,787,241 issued to Clark on Apr. 2, 1957.

The terms "panty liner" or "pantiliner" refer to absorbent articles thatare less bulky than sanitary napkins which are generally worn by womenbetween their menstrual periods. Suitable absorbent articles in the formof pantiliners are disclosed in U.S. Pat. No. 4,738,676 entitled"Pantiliner" issued to Osborn on Apr. 19, 1988.

The term "incontinent article" refers to pads, undergarments (pads heldin place by a suspension system of same type, such as a belt, or thelike), inserts for absorbent articles, capacity boosters for absorbentarticles, briefs, bed pads, and the like, regardless of whether they areworn by adults or other incontinent persons. Suitable incontinentarticles that can be provided with the extensible components describedherein are disclosed in U.S. Pat. No. 4,253,461 issued to Strickland, etal. on Mar. 3, 1981; U.S. Pat. Nos. 4,597,760 and 4,597,761 issued toBuell; the above-mentioned U.S. Pat. No. 4,704,115; U.S. Pat. No.4,909,802 issued to Ahr, et al.; U.S. Pat. No. 4,964,860 issued toGapson, et al. on Oct. 23, 1990; and in U.S. patent application Ser.Nos. 07/631,090 and 07/637,571 filed respectively by Noel, et al. andFeist, et al. on Jan. 3, 1991.

The focus of the present invention is on absorbent articles that areintended to be worn in the crotch region of the wearer's undergarments.However, the features of the present invention could also be used inabsorbent articles such as diapers. Diapers are absorbent articles wornby infants and incontinent persons that are fastened about the waist ofthe wearer.

Suitable diapers that can be provided with the extensible featuresdescribed herein are disclosed in U.S. Pat. No. 3,860,003 issued toBuell on Jan. 14, 1975, and U.S. patent application Ser. No. 07/715,152filed in the name of Buell, et al. on Jun. 13, 1991.

The disclosures of all patents, patent applications (and any patentswhich issue thereon, as well as any corresponding published foreignpatent applications), and publications mentioned throughout this patentapplication are hereby incorporated by reference herein. It is expresslynot admitted, however, that any of the documents incorporated byreference herein teach or disclose the present invention. It is alsoexpressly not admitted that any of the commercially available materialsor products described herein teach or disclose the present invention.

5. Test Methods

The extensibility of the sanitary napkin (or other absorbent article) ismeasured on EME Tensile Tester, Model No. 559A available from EME, Inc.,P.O. Box 187, Newbury, Ohio 44065, a constant rate of elongation tensiletesting apparatus.

The EME Tensile Tester is provided with a computer that provides an LCDreadout of the distance the ends of the clamps are spaced from areference home position and the forces on the sample when the clamps arespaced various distances from the home position.

All tests are performed at 50% humidity and at 73° F. The samples arecarefully handled to avoid any stretching of the same prior toperforming the test. The tests should each be repeated with samplestaken from five separate products of the same type. If any of thesamples fall within the claimed range or limit, the product will beconsidered to fall within the scope of the appended claims.

A. Method to Measure Extensibility of One Inch (2.5 cm.) Center Strip

Step 1 Sample for Measuring Longitudinal Extensibility

Cut a 1.0 inch (2.54 cm.) wide strip from the center of the absorbentarticle using a JDC Precision Sample Cutter, Model #1-12 available fromThwing-Albert, Philadelphia, Pa. The strip used as the sample for thismethod should be cut along the longitudinal centerline of the absorbentarticle. The length of the strip should run the full length of theportion of the absorbent article from which the sample is taken.

Sample for Measuring Transverse Extensibility

A 1.0 inch wide strip is cut from parallel to the transverse centerlineof the absorbent article using the JDC sample cutter. The strip used asthe sample for measuring the transverse extensibility can be cut throughany one inch wide section of the absorbent article that runs parallel tothe transverse centerline. The sample need not run along the transversecenterline.

The sample should, however, be cut through a portion of the absorbentarticle so that the entire one inch width of the sample consists of atleast one of the absorbent components of the absorbent article. (Theterm "absorbent component" is defined below.) Thus, the sample shouldnot be cut so close to one of the transverse end edges of the absorbentarticle that the sample contains portions of the absorbent article atthe end seal.

Samples for Measuring Both Longitudinal and Transverse Extensibility

A sample for measuring longitudinal extensibility should be cut from afirst sample absorbent article. The sample for measuring transverseextensibility should be cut from a second sample absorbent article ofthe same type as the first (i.e., an identical product). (The sameapplies to any of the other tests described herein when a sample is cutout of the product to measure extensibility in a given direction.)

Step 2

Remove any adhesive cover strip from the sample. If the sample has anadhesive fastener, eliminate any adhesive tack by dusting the adhesivefastener with talc or corn starch.

Step 3

Lay the sample unrestrained on a table with the body surface facingupward. Measure the length of the sample to the nearest 0.1 inch (0.25cm.).

The length of the sample, for the purpose of the appended claims, is thedimension of the sample that runs perpendicular to the one inch widthdimension. The length of the sample is obtained by measuring the lengthof the absorbent components of the sample. (This can be contrasted withdetermining the length of the sample by simply measuring the overalllength of the sample.)

The length of the sample is equal to the length of the longest absorbentcomponent of the sample. If the sample is folded or curved (i.e., whenit is removed from its package), flatten the ends of the sample prior tomeasuring the length of this absorbent component. The sample isflattened by placing a ruler on top of the sample and gently pressingdown on the portion of the ruler that covers the ends of the sampleuntil the garment surface at the ends lies flat against the table.

The term "absorbent component", as used herein, refers to componentsthat are generally used as the primary absorbent component of theproduct, such as the absorbent core of the product. It also includesabsorbent components, such as the secondary topsheets described hereinthat serve a wicking or storage function. The term absorbent component,however, excludes components that are generally only used as thetopsheet or backsheet of the absorbent article.

The measurement of the length of the longest absorbent component takenabove should not include any portions of the absorbent component thatmay be located outboard of, or within any end seal on the sample becausethese portions of the absorbent component typically serve no absorptivefunction.

Step 4

Clamp each end of the sample in the tensile testing apparatus using 3inch (7.6 cm.) wide clamps. The clamps of the tensile tester are set sothat they will be pulled away from each other in opposite directions(that is, they will pull at an angle of 180 degrees). The sample shouldbe centered in the clamps and the clamping pressure should be sufficientto prevent any slippage of the sample in the clamps (this applies to allof the test methods).

The sample should be clamped so that the outermost edge (i.e., the freeend) of the clamps are approximately 0.5 inches (about 1.3 cm.) inwardfrom the end edges of the longest absorbent component. The portions ofthe sample that may be located within or outboard of an end seal on thesample are excluded when determining the location of the end edges ofthe longest absorbent component for placing the clamps of the testingapparatus on the sample.

Step 5

Set the gauge length of the tensile tester to the length of theabsorbent component (as measured above) less the amount of absorbentcomponent material clamped into each of the clamps (typically 1 inch).Initiate the elongation with a cross head speed of 0.367 inches persecond (0.93 cm. per second).

When the sample reaches the gauge length, tare the load cell of thetesting apparatus to zero. Set the trigger point to begin collectingdata at 20 grams force. (The application of this initial 20 gram forcetypically pulls out at least some of any slack that may exist in thesample.)

The force and extensibility measurements are taken at the desired times,and the test is completed. The initial length of the sample is themeasured length of the longest absorbent component. The force, for thepurpose of the appended claims, is the actual force reading on thetesting apparatus when the above procedure is followed.

The cutting of the 1.0 inch strips is intended to minimize the effect ofany elastic strands in the longitudinal side margins of the absorbentarticle on the results of the test. (The absorbent articles of thepresent invention are preferably free of such elastic strands. Optionalelastic strands can, however, be added.)

When measured according to this test, 1.0 inch strip of the absorbentarticle is preferably capable of extension in the longitudinal directionof greater than or equal to about 105%, 110%, 115%, 120%, 125%, or more,of its initial length when subjected to a force of less than or equal toabout 20, 50, 100, 150, 200, 300, 400, or 500 grams. The 1.0 inch stripof the absorbent article is preferably capable of extension in thetransverse direction when subjected to forces of the same amounts. Thestrip can have a maxima extension under these forces of up to 110, 120%,130% 140%, 150%, 160%, 170%, 180%, 190%, 200%, or more. The limitsspecified in this specification can be combined in any manner in theappended claims.

The absorbent article may be capable of such extension as measured by a1.0 inch strip in both the longitudinal and transverse directions. Insuch a case, the absorbent article is preferably extensible in theamounts specified in the foregoing paragraph.

Although the absorbent article can be of any length, preferably, theabsorbent article is worn in an undergarment and has a longest absorbentcomponent, such as an absorbent core, with an initial length of lessthan or equal to about 12.0 inches. The width of the absorbent componentof the absorbent article is preferably less than or equal to about 3.0inches, and is more preferably less than or equal to about 2.5 inches.(Diapers, on the other hand, typically have absorbent cores greater thanabout 12.0 inches in length and 3.0 inches in width.) In addition, insome embodiments, the absorbent article may have a caliper of less thanor equal to about 5 mm.

The absorbent article preferably has a force wall such that the striprequires a force greater than or equal to 1,000 grams to extend beyond160%, 150%, 140%, 130% of its initial length, or one of the otherlengths specified above.

The absorbent article is preferably also elastically extensible orpermanently deformable such that when the strip is extended to one ofthe above lengths, it is capable of recovering to a recovered dimensionthat is less than or equal its extended length when the extending forcesare removed.

B. Method to Measure Extensibility of Absorbent Article

The sample used for this test is the entire absorbent article. This testis used only to measure the longitudinal extensibility of the absorbentarticle. The transverse extensibility is measured according to thepreceding test method.

The entire absorbent article used as the sample in this test should betested following steps (2)-(5) above, with the following additionalinstruction when carrying out step (3).

If the sample cannot be conveniently flattened (such as due to thepresence of contracted elastics), the length of the longest absorbentcomponent should be measured by allowing the sample to unfold (if it isfolded) and holding the sample in the curved configuration that thesample is in when it is taken out of the box, and measuring the lengthof the longest absorbent component with a tailor's cloth tape measurealong the arc formed by the garment surface of the absorbent article.

The absorbent article is preferably capable of extension in thelongitudinal direction (i.e., along the longitudinal centerline) ofgreater than or equal to about 105%, 110%, 115%, 120%, 125%, 130%, 140%,150%, 160%, 170%, 180%, 190%, 200%, or more, of its initial length whensubjected to a force of less than or equal to about 20, 50, 100, 150,200, 300, 400, 500, 600, 700, 800, 900, 1,000, or more grams. (Theforces for longitudinal extensibility may be higher than those measuredon the 1.0 inch strip by the previous test since the entire absorbentarticle is used in this second test,)

The absorbent article preferably has a force wall such that the striprequires a force greater than or equal to 1,200, 1,500 or 2,000 grams toextend beyond 160%, 150%, 140%, 130% of its initial length, or one ofthe other lengths specified above.

C. Method to Measure Stretch Relative to Product Shear from anUndergarment

1. First Method--20 Gram Trigger

The sample used for this test is the entire absorbent article.

Lay the sample unrestrained on a table with the body surface facingupward. Measure the length of the longest absorbent component of thesample to the nearest 0.1 inch (0.25 cm.). Follow the same instructionsfor measuring the absorbent component in step (3) of Test Methods A andB above. This test, however, is only concerned with the measurement ofproperties of the sample in the longitudinal direction (i.e., parallelto the longitudinal centerline).

If the sample has an adhesive fastener, remove any adhesive cover stripfrom the sample. Take a strip of cotton fabric #429W (standard 3 inchwidth) manufactured by Test Fabrics, Inc. of Middlesex, N.J., and cover1.0 inch (2.54 cm.) of the fastener at one end of the fastener.

The sample can be placed under an ultraviolet lamp to aid in determiningthe end of most adhesive fasteners. Eliminate any adhesive tack on theremainder of adhesive fastener by dusting the uncovered portion of theadhesive fastener with talc or corn starch.

The strip of cotton fabric should be long enough so that its free end(unattached end) extends at least 0.5 inch (1.3 cm.) beyond the end edgeof the sample (i.e., the actual end edge of the product includingabsorbent and nonabsorbent components) adjacent to the 1 inch portion ofthe fastener that the cotton strip covers.

Apply 0.25 psi. of pressure for a period of 30 seconds uniformly (with aweight) to the cotton surface to attach the cotton fabric to thefastener. If the panty fastener is not adhesive, attach the sample tothe cotton fabric in the manner the fastener would ordinarily be placedin the wearer's undergarment.

Clamp the end of the sample that is not attached to the cotton strip inthe tensile testing apparatus using a 3 inch (7.6 cm.) clamp. The sampleshould be clamped so that the outermost edge (i.e., the free end) of theclamp is approximately 0.5 inches (about 1.3 cm.) inward from the endedge of the absorbent component. If there is more than one absorbentcomponent, the sample should be clamped so that all of the absorbentcomponents are grabbed by the clamp. In other words, the sample isclamped about 0.5 inches from the end of the absorbent component(s).

Place the free end of the cotton strip into the other 3 inch clamp. Thefree end of the cotton strip is placed in this clamp so that the freeend of the clamp just comes into contact with the nearest end edge ofthe sample. The clamps of the tensile tester are set so they will pullat 180 degrees (as in the preceding tests). This will impart shearingforces which tend to separate the fastener and the cotton strip fromeach other.

Set the gauge length of the tensile tester to the length of theabsorbent component (measured above) less the amount of absorbentcomponent material clamped into each of the clamps (typically about 0.5inch). Initiate the elongation with a cross head speed of 0.367 inchesper second (0.93 cm. per second). When the sample reaches the gaugelength, tare the load cell of the testing apparatus to zero. Set thetrigger point to begin collecting data at 20 grams force.

The force and extensibility measurements are taken at the desired times,and the test is completed.

The absorbent article is preferably capable of extending at least about) 110%, 115%, 120%, 125%, 130%, 140%, etc. of its initial length beforeit is subjected to a force of an additional 1,000 grams, or before theforces exerted on the sample cause the fastener to separate from thecotton fabric when tested under the above test (Test Method (C)(1))

2. Second Method--50 Gram Trigger.

The sample used for this test is the entire absorbent article. This testis only concerned with the measurement of properties of the sample inthe longitudinal direction (i.e., parallel to the longitudinalcenterline).

Lay the sample unrestrained on a table with the body surface facingdownward. If the sample has an adhesive fastener, peel back enough ofany adhesive cover strip to expose about 2 inches (about 5 cm.) ofadhesive on one end of the sample.

Take a strip of cotton fabric #429W (standard 3 inch width) manufacturedby Test Fabrics, Inc. of Middlesex, N.J., and cover 1.0 inch (2.54 cm.)of the (exposed) fastener material at the end of the fastener. Thesample can be placed under an ultraviolet lamp to aid in determining theend of most adhesive fasteners. The portion of the fastener covered bythe cotton should be representative of the fastening surface. Just placethe cotton strip on the fastener. Do not apply pressure at this point.

The strip of cotton fabric should be long enough so that its free end(unattached end) extends at least 0.5 inch (1.3 cm.) beyond the end edgeof the sample (i.e., the actual end edge of the product includingabsorbent and nonabsorbent components) adjacent to the 1.0 inch portionof the fastener that the cotton strip covers. A strip of cotton whichextends about 3 inches (about 7.6 cm.) beyond the end edge of the sampleis sufficient for many samples.

Measure and mark a transverse line 0.5 inch (1.3 cm.) from the edge ofthe longest absorbent component at the opposite end of the sample (theend that will be the attached end of the sample). This mark serves as aguide for the location of the clamp of the tensile tester at this end ofthe sample.

Apply 0.25 psi. of pressure for a period of 30 seconds uniformly (with afoam-covered weight) to the cotton surface to attach the cotton fabricto the fastener. If the panty fastener is not adhesive, attach thesample to the cotton fabric in the manner the fastener would ordinarilybe placed in the wearer's undergarment. Remove the weight. Remove anyremaining release paper. Eliminate any adhesive tack on the remainder ofany adhesive fastener. This may be done by dusting the uncovered portionof the adhesive fastener with talc or corn starch.

Clamp the end of the sample that is not attached to the cotton strip inthe tensile testing apparatus using a 3 inch (7.6 cm.) clamp. The sampleshould be clamped so that the outermost edge (i.e., the free end) of theclamp is 0.5 inches (1.3 cm.) inward from the end edge of the absorbentcomponent. If there is more than one absorbent component in the 1/2 inchregion, the sample should be clamped so that all of the absorbentcomponents are grabbed by the clamp. In other words, the sample isclamped 0.5 inches from the end of the absorbent component(s).

Place the free end of the cotton strip into the other 3 inch clamp. Thefree end of the cotton strip is placed in this clamp so that the freeend of the clamp just comes into contact with the nearest end edge ofthe sample. Care should be taken not to clamp any portion of this end ofthe sample. The clamps of the tensile tester are set so they will pullat 180 degrees (as in the preceding tests). This will impart shearingforces which tend to separate the fastener and the cotton strip fromeach other.

Set the distance between the clamps of the tensile tester so there isexcess material (or slack) in the sample. Thus, the sample should not beunder tension at this point.

Initiate the elongation a cross head speed of 0.367 inches per second(0.93 cm. per second). If the sample has an adhesive fastener, theelongation should be initiated within 30 seconds after the removal ofthe 0.25 psi. foam covered weight used to fasten the sample to thecotton strip. Set the trigger point to begin collecting force andelongation data at 50 grams force. The cross head should travel untilthe cotton separates (i.e., shears) from the 1.0 inch section of thesample's fastener.

The force and extensibility measurements are taken at the desired times,and the test is completed. The guage length used to calculate %elongation is the linear distance from the free end of the stationaryjaw (the jaw that clamps 0.5 inches inward from the end of the absorbentcomponent at the end of the sample opposite the end of the sampleadhered to the cotton strip) to the nearest end edge of the cottonfabric when the sample is subjected to 50 grams of tensile force.

The absorbent article is preferably capable of extending at least about110%, 115%, 120%, 125%, 130%, 140%, etc. of its initial length before itis subjected to a force of an additional 800 or 1,000 grams, or beforethe forces exerted on the sample cause the fastener to separate from thecotton fabric when tested under the above test (Test Method (C)(2)),

The tests in Test Method C are intended to simulate the conditions underwhich an absorbent article will stretch when attached to anundergarment.

D. Method to Measure Rate of Return of Absorbent Article HavingElasticity

The sample used for this test is the entire absorbent article. This testis also only concerned with the measurement of properties of the samplein the longitudinal direction (i.e., parallel to the longitudinalcenterline).

Measure the maximum longitudinal extension of the sample at 1,000 gramsforce using Test Method B above.

The following test is conducted by hand. Remove any adhesive cover stripfrom the sample. If the sample has an adhesive fastener, eliminate anyadhesive tack by dusting the adhesive fastener with talc or corn starch.

Place a ruler with a scale in either 0.1 inch increments or 1 mm.increments on a table.

Grasp one end of the sample with one hand. The end of the sample shouldbe grasped approximately 11/2 inches (about 3.8 cm.) from the transverseend edge of the product. The sample should be held so that it is as flatand horizontal across its width as possible.

Hold the sample either over the ruler or next to the ruler with the bodysurface of the sample facing upward so that the scale on the ruler canbe observed throughout the test. The sample should be held so that theportions of the sample approximately 0.5 inches (1.3 cm.) inward fromthis fixed end of the sample are firmly held even with the beginning ofthe scale on the ruler throughout the test.

Place a digital stop watch which can record time to the nearest 0.01second next to the ruler and the sample. Position a video camera overthe articles on the table so that the sample can be observed and theelapsed time on the stop watch can be simultaneously observed andrecorded to the nearest 0.1 second.

Grasp the other transverse end edge (i.e., the free end) of the sample.The sample should be grasped at an area approximately two inches (about5 cm.) wide centered about the longitudinal centerline. The sampleshould be grasped in this area about 0.5 inch (about 1.3 cm.) inwardfrom the end edge of longest absorbent component. (The 0.5 inch distanceshould not include any portion of the absorbent component in or outboardof a product end seal as described above.)

Turn on the video recorder and the stop watch. Gradually extend the freeend of the sample so that the sample extends to its maximum extension at1,000 grams (measured earlier) or to 120% of its original length,whichever is greater. The extension process should be completed in lessthan or equal to 30 seconds.

Release the free end of the sample. The timing on the stop watch startswhen the free end is released.

Determine the distance the sample recovers toward its original lengthand the time it takes to recover toward its original length at thedesired points by playing back the video tape on a video cassetterecorder frame by frame and observing any contraction of the sample.

Calculate the rate of recovery by dividing the distance the sampleretracts (converted to centimeters) by the time required to travel thecorresponding distance. This completes the test.

The sample in Test Method D can also be clamped into the clamps of atensile testing machine, and the test performed in a similar manner withone end of the sample being placed in a stationary clamp, and the otherin a clamp that is capable of intantaneously releasing that end of thesample at the desired time.

When the absorbent article is subjected to tensile forces to extend saidabsorbent article along its longitudinal centerline to: (a) its maximumextended length at 1,000 grams, or (b) 120% of its original length,whichever is greater, and said tensile forces are removed, saidabsorbent article, if extended to its maximum extended length, recoversfrom (a)(i) its maximum extended length toward its recovered length(a)(ii) a distance of its maximum extended length less 10% its originallength, or if extended to 120% of its original length, recovers to 110%of its original length at a rate of recovery of less than or equal toabout 20, 30, or 40 cm./second.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention.

What is claimed is:
 1. An extensible absorbent article for wearing inthe crotch region of an undergarment, said absorbent article having alongitudinal centerline, a transverse centerline, an absorbent articleinitial length, a liquid pervious side, a liquid impervious side, and anabsorbent component positioned between said liquid pervious side andsaid liquid impervious side, wherein:(a) said absorbent article iscapable of extension along said longitudinal centerline of greater thanor equal to about 110% of the absorbent article initial length whensubjected to a force of less than or equal to about 1,000 grams; and (b)a 1.0 inch wide strip having a strip initial length is cut from atransverse section that runs parallel to the transverse centerline ofsaid absorbent article is capable of extension of greater than or equalto about 110% of its initial length when subjected to a force of lessthan or equal to about 400 grams wherein at least a portion of theextension of the strip is provided by at least the material locatedtransversely inboard of the side edges of the absorbent component. 2.The absorbent article of claim 1 wherein said absorbent article iscapable of extension to an extended length of greater than or equal toabout 110% of its initial length when subjected to a force betweengreater than or equal to about 50 grams and less than or equal to about1,000 grams.
 3. An extensible absorbent article for wearing in thecrotch region of an undergarment, said absorbent article having alongitudinal centerline, a transverse centerline, an absorbent articleinitial length, a liquid pervious side, a liquid impervious side, and anabsorbent component positioned between said liquid pervious side andsaid liquid impervious side, wherein:(a) said absorbent article iscapable of extension along said longitudinal centerline of greater thanor equal to about 110% of the absorbent article initial length whensubjected to a force of less than or equal to about 1,000 grams, whereinat least a portion of the extension of the absorbent article is providedby the material located longitudinally inboard of the ends of theabsorbent component; and (b) a 1.0 inch wide strip having a stripinitial length is cut from a transverse section that runs parallel tothe transverse centerline of said absorbent article is capable ofextension of greater than or equal to about 110% of its initial lengthwhen subjected to a force of less than or equal to about 400 grams. 4.An extensible absorbent article for wearing in the crotch region of anundergarment, said absorbent article having a longitudinal centerline, atransverse centerline, an absorbent article initial length, a liquidpervious side, a liquid impervious side, and an absorbent componentpositioned between said liquid pervious side and said liquid imperviousside, wherein:(a) said absorbent article is capable of extension alongsaid longitudinal centerline of greater than or equal to about 110% ofthe absorbent article initial length when subjected to a force of lessthan or equal to about 1,000 grams, wherein at least a portion of theextension of the absorbent article is provided by the material locatedlongitudinally inboard of the ends of the absorbent component; and (b) a1.0 inch wide strip having a strip initial length is cut from atransverse section that runs parallel to the transverse centerline ofsaid absorbent article is capable of extension of greater than or equalto about 110% of its initial length when subjected to a force of lessthan or equal to about 400 grams wherein at least a portion of theextension of the strip is provided by at least the material locatedtransversely inboard of the side edges of the absorbent component.